,,the ,,common ,,rocks ,,and ,,minerals ,,of ,,missouri ,w4 ,d4 ,,keller ,,university ,,of ,,missouri ,,press ,,columbia ,university of ,missouri ,press1 ,columbia1 ,missouri #febja ,,isbn #j-hbfb-jehe-b ,library of ,congress ,card ,number #fg-ffagc ,printed and bound in the ,united ,states of ,america ,all rights reserved ,first ,edition #aide ,revised ,editions #aidh1 #aifa ,reprinted #aiga1 #aigc1 #aigh1 #aihf1 #aihi1 #aiib1 #bjjd ,,table ,,of ,,contents ,page ,,introduction #e ,,determinative ,,key #f ,,rock ,,and ,,mineral ,,description #aj ,limestone and ,dolomite #aj 8,cotton ,rock0 ,limestone #ae ,marble #ae ,cave ,onyx and ,deposits #af ,travertine #af ,calcite #af ,dolomite #ah ,shale #bj ,fire ,clay #bd ,plastic ,fire ,clay #bf ,flint ,fire ,clay #bf ,diaspore #bg ,burley ,clay #bi ,sandstone #cj ,chert1 ,flint #cd ,weathered ,chert #cf 8,kaoleen0 #cg ,tripoli #cg ,agate #cg ,jasper #ch ,granite #ch ,quartz #da ,feldspar #dc ,mica #dd ,porphyry1 ,rhyolite #de ,basalt #df ,gabbro1 ,diabase #dh ,goal #di ,pyrite1 ,marcasite #ea ,conglomerate #ed ,gneiss #ed ,hematite #ef ,limonite #eg ,paint ,ore1 ,ochre #eh ,iron ,band ,diaspore #eh ,manganese ,ore #eh ,galena #ei ,sphalerite #fj ,barite #fa ,gypsum #fc ,meteorites #fd ,gold #fe ,silver #fe ,diamonds #fe ,uranium ,minerals #fe ,,miscellaneous ,,rock ,,structures #ff ,concretions #ff ,geodes #fg ,fossils #fi ,arrow ,heads1 ,artifacts #ga ,,the ,,rocks ,,of ,,missouri #ga ,,minerals ,,of ,,missouri #gd ,,geological ,,values #gd ,,index #gf ,,introduction ,missourians are interested in the rocks and minerals which they find on their farms1 in excavations1 and while on their vacation trips4 ,some of the specimens are unusual in shape or appearance1 some are crystalline and beautiful1 some may be ores of economic importance1 but many simply arouse the curiosity of the finder4 ,many of these specimens are received each year at the ,university at ,columbia1 and each is usually accompanied by a request for information on the correct name for the specimen1 its composition1 its commercial value1 and the manner of its formation4 ,frequently the requests include questions of a broader geological nature1 or seek the recommendation of a general1 easily-read book written on rocks and minerals which may be purchased at a book store or consulted at a library4 ,moreover1 many persons ask how they may determine for themselves the geological specimens which they have collected4 ,this little booklet has been prepared with the intention of answering the questions most commonly asked by citizens of the state about ,missouri rocks and minerals4 ,descriptions and photographs of ,missouri rock and mineral occurrences are provided1 and essential facts about the geological conditions of their formation are simply told4 ,a determinative key is supplied in order that the reader may identify and name most of the common specimens which he collects within the state 7and elsewhere1 also74 ,no special determinative equipment will be suggested1 and only non-technical language will be employed because the chief objective here is to furnish a useful1 understandable geological account of the common ,missouri rocks and minerals to the average person without geological training4 ,in fact1 for the purposes of identification no differentiation is made between mineral and rock1 although the professional geologist does separate them in definition4 ,for our purpose1 a rock is an aggregate of mineral particles1 but a mineral is a substance 7without life7 having more definite and constant properties than a rock4 ,for those interested further1 more technical and more nearly correct definitions1 with explanations1 are given at the back1 on page #gd4 ,the rarer minerals and those requiring special equipment for determination may be sent to the ,department of ,geology of the ,university of ,missouri at ,columbia for identification free of charge4#a ,names used locally1 and sometimes incorrectly from a strictly technical sense1 for rocks and minerals will follow the generally accepted names1 and both will be duplicated in the index at the back of the pamphlet to facilitate finding either one4 ,,determinative ,,key ,a rock or mineral specimen which is unfamiliar to the collector may be identified by using the information in this booklet in either of two ways3 7#a7 the reader may turn through the pages and compare his specimen with the photographs of others named there and read their descriptions until he finds a match for his specimen2 or 7#b71 the better way1 he may classify his specimen first by the use of the determinative key which follows and be directed thereby to the pages in the book for confirmation of the name by the photographs1 description1 and discussion of the substance4 ,the writer recommends the second method and has prepared this booklet on the assumption that the determinative key will be used4 ,the simplest and probably the best means of separating specimens of different rocks and minerals is on the basis of hardness1 which means resistance to scratching4 ,crushing strength is different from hardness2 therefore1 in testing for hardness1 do not attempt to pulverize4 ,merely determine if the specimen can be scratched with the substance indicated4 ,determination of the mark or 8streak0 of a mineral when rubbed on a hard white rock or unglazed porcelain is demonstrated in the photograph on page #ef4 ,a4 ,specimens that can be scratched readily with the ,,thumb ,,nail4 #a4 ,become muddy when rubbed with a wet finger4 ,page ,shale #bj ,fire ,clay #bd ,flint ,fire ,clay #bf ,diaspore ,clay #bg #b4 ,crumble easily into hard sand grains4 ,sandstone #cj #c4 ,chalky1 white1 porous4 ,tripoli #cg ,weathered ,chert #cf 8,cotton ,rock0 ,dolomite #ae #d4 ,clear and glassy1 or glistening white2 may split and show glassy1 flat faces4 ,gypsum #fc ,b4 ,specimens scratched readily with a ,,pocket ,,knife1 or ,,iron ,,nail but not with the thumb nail4 #a4 ,loose sand grains scratched off4 ,sandstone #cj #b4 ,granular1 but grains are tightly interlocked2 also 8bubbles0 or effervesces in dilute muriatic 7hydrochloric7 acid4 ,limestone #aj ,dolomite #aj ,marble #ae ,formed in a cave4 ,cave ,onyx #af ,travertine #af #c4 ,chalky white1 porous4 ,weathered ,chert #cf #d4 ,black4 ,coal #di ,black ,shale #bj #e4 ,pebbles or gravel cemented together4 ,conglomerate #ed #f4 ,powder becomes muddy when wetted4 ,hard ,shale #bj ,flint ,fire ,clay #bf ,diaspore ,clay #bg #g4 ,intense red2 leaves a red mark or streak when rubbed on a hard white rock or on unglazed porcelain4 ,hematite #ef ,iron ,band ,diaspore #eh ,paint ,ore #eh #h4 ,yellow1 brown1 or black and leaves a yellow-to-brown mark or streak when rubbed on a hard white rock or on unglazed porcelain4 ,limonite #eg ,ochre #eg #i4 ,heavy1 black1 leaves a black or brownish black mark or streak when rubbed on a hard white rock or on unglazed porcelain4 ,manganese ,ore #eh #aj4 ,heavy1 with bright metallic luster1 and lead-colored on a freshly broken surface4 ,galena #ei #aa4 ,looks like rosin1 or may be ruby-colored or black1 but has a high resinous luster on freshly broken surface4 ,sphalerite #fj #ab4 ,glassy luster2 water-white1 milky1 honey-colored1 pink1 gray2 may occur in six-sided crystals1 sometimes pyramid-shaped2 always breaks with flat glistening faces2 always reacts in the lump with cold dilute muriatic 7hydrochloric7 acid4 ,calcite #af #ac4 ,like calcite above but may have a pink1 pearly luster and curved crystal faces2 reacts with cold dilute acid when powdered but not readily in lump form4 ,dolomite #ah #ad4 ,opaque white1 glassy or bluish1 very heavy1 lustrous on freshly broken surface2 does not react with acid4 ,barite #fa #ae4 ,flaky1 micaceous like 8isinglass04 ,mica #dd ,c4 ,specimens ,,too ,,hard to be scratched readily on a fresh surface with a pocket knife or iron nail2 weathered specimens may be slightly scratched4 #a4 ,very fine-grained throughout1 compact2 occurs in nodules1 pebbles2 breaks with a slick1 curved1 oyster-shell-like 7conchoidal7 fracture4 ,chert1 if white1 gray or stained yellow or red #cd ,flint1 if black #cd ,agate1 if banded #cg ,petrified ,wood1 if it shows the grain or bark of wood #cg #b4 ,granular like sandstone but extremely hard and breaks through the grains as readily as around them4 ,quartzite #da ,quartzitic ,sandstone #cj #c4 ,fine-grained1 dark green to dark gray to greenish black2 occurs in boulders north of ,missouri ,river and in the granite and porphyry country or southeastern ,missouri4 ,basalt #df #d4 ,very fine-grained1 compact1 pink1 red1 brown1 gray2 usually 8freckled0 or sprinkled with grains about #a_/af inch in diameter4 ,porphyry #de ,rhyolite #de ,rhyolite ,porphyry #de #e4 ,coarse-grained 7,,bb-shot size to considerably larger71 glassy luster where freshly broken2 pink1 red1 grey4 ,granite #ch ,gneiss1 like granite but banded2 occurs in boulders north of the ,missouri ,river #ch #f4 ,coarse-grained1 dark green1 dark gray1 greenish-black4 ,gabbro #ed ,diabase #dh #g4 ,brassy1 metallic1 heavy2 leaves a black to greenish black mark or streak when rubbed on a hard white rock or on unglazed porcelain4 ,pyrite #ea ,marcasite #ea #h4 ,glassy fragments breaking with rough fracture1 or may occur in six-sided crystals2 clear1 water-white1 milk-white1 gray or pink2 in sand grains2 in granite4 ,quartz #da #i4 ,intense red2 leaves a red mark or streak when rubbed on a hard white rock or on unglazed porcelain4 ,hematite #ef ,iron ,band ,diaspore #eh ,paint ,ore #eh #aj4 ,yellow1 brown or black1 but leaves a yellow to brown mark or streak when rubbed on a hard white rock or on unglazed porcelain4 ,limonite #eg ,,rock ,,and ,,mineral ,,descriptions ,limestone and ,dolomite ,limestone is a bedded or layered rock found abundantly in ,missouri in bluffs1 creek beds1 hill sides1 and is known to underlie the soil in most of the south half of the state4 ,it occurs in thin slabs1 thick layers1 and in massive beds which may make a small cliff in themselves4 ,limestone is soft enough to be scratched with steel4 ,it is commonly white to grayish1 but may be stained tan1 yellowish1 or reddish by iron oxide1 or darkened through shades of gray to black by the presence of very finely-divided1 black carbonaceous matter4 ,it may be microscopically fine-grained 7and then it can be used in lithographic printing in the reproduction of very fine images71 or its grains may vary in size up to one-half inch in cross section4 ,illustration3 ,limestone 7dolomite7 bluff near ,jefferson ,city4 ,it is determined as limestone with certainty by wetting with dilute cold acid2 then it 8bubbles0 or effervesces1 and eventually dissolves entirely4 ,ordinary or regular limestone contains the mineral calcite1 but the magnesian variety of limestone1 dolomite1 contains the mineral dolomite1 which does not effervesce freely in lump size in dilute acid1 but which does effervesce when powdered or when treated with hot acid or concentrated acid4 ,the preferred acid to use is muriatic 7hydrochloric1 the 8not-cut0 soldering acid7 diluted one part of acid to one part of water4 ,caution6 ,this acid mixture should be stored in a glass or porcelain container away from children or animals6 ,acid strong enough to dissolve rock will ruin clothes1 destroy flesh1 and is poisonous6 ,dilute sulphuric 7storage battery7 acid will also give the effervescence test1 and the acid of very strong vinegar will react with limestone slowly4 ,in making the test it should be recognized that the limestone which acts as a cement in sandstone1 or limestone impurities in shale will also effervesce1 but those minor parts of the rock will dissolve and leave the residues of sandstone or shale1 which are insoluble4 ,illustration3 ,a coarse-grained limestone effervescing in dilute muriatic acid4 7,this photograph and other close-up views taken by ,j4 ,f4 ,barham and ,allen ,barnes1 ,university photographers47 ,illustration3 ,solid dolomite does not effervesce in dilute acid4 ,note the white rock powder scrapings adjacent4 ,illustration3 ,dolomite powder does effervesce in dilute muriatic acid4 ,not all dolomite is this fine in grain4 ,some limestones are chemical deposits but many are consolidated accumulations of fossil shells and shell fragments--organic limestone4 ,for example1 a widespread limestone1 the so-called ,burlington limestone1 extending across central ,missouri1 contains many crinoid stem fragments and plates1 attesting to the abundance of crinoids living in the sea at the time this limestone was laid down4 ,crinoids are sea animals which1 because of their branching structure and superficial resemblance to plants1 have been nicknamed 8sea lilies40 ,except for calcareous cave and spring deposits1 almost all limestone formations in ,missouri contain a few fossils of animals which lived in the ocean1 and therefore ,missouri limestones are considered marine in origin4 ,they offer evidence for the very interesting land-sea changes which this state has undergone in the geologic past4 ,illustration3 ,limestone composed almost entirely of crinoid 7marine animal fossil7 stem plates1 from near ,columbia4 ,pure limestone is composed of #ajj calcium carbonate 7calcite mineral71 whereas pure dolomite contains #ed4ce calcium carbonate and #de4fe magnesium carbonate 7dolomite mineral74 ,magnesium carbonate has slightly higher acid-neutralizing properties than calcium carbonate1 weight for weight1 and because analyses of limestone to be used for soil sweetening and agricultural fertilizer purposes are commonly reported in calcium carbonate equivalents1 a dolomite or dolomitic limestone may be reported over #ajj calcium carbonate equivalent4 ,unless one understands the full meaning of the report he may be bewildered by a statement of the value over #ajj4 ,the calcium and magnesium which form limestone 7or dolomitic limestone7 in the ocean are carried there in solution by the streams which drain the land4 ,rain water percolating through the ground and rocks becomes slightly acidified with carbon dioxide 7like the carbonated water in beverages7 and dissolves the calcium and magnesium from primary igneous rocks like gabbro and basalt which are weathering1 or from preexisting limestones which primitively were derived from igneous rocks4 ,this calcium and magnesium in solution are responsible for the hardness of the water4 ,in fact1 the hard water in ,missouri springs1 wells1 and streams is hard because it contains either or both calcium 78lime07 and magnesium in solution4 ,this soluble calcium and magnesium flows on in the stream to the ocean because of its combination with the dissolved carbon dioxide4 ,in the shallow parts of the ocean1 as on the continental shelves where the water is less than #fjj feet deep1 the limestone is deposited in layers just like the white lime layer deposits on the bottom of the teakettle in which hard water has been boiled4 ,chemical processes1 temperature changes1 evaporation of the ocean water1 and organisms are responsible for most of the limestone deposition4 ,extensive limestone deposition is taking place today off the coast of ,florida and around the tropical islands of the southern ,pacific4 ,the uses of limestone are numerous4 ,it is an excellent building stone in either the rough1 sawn1 or dressed state4 ,it is used for rubble stone1 rip-rap1 railroad ballast1 crushed gravel1 and aggregate in concrete4 ,it is one of the raw materials of ,portland cement4 ,quicklime and hydrated lime are prepared from limestone which has been heated to drive off the chemically combined carbon dioxide4 ,limestone is added as a fluxing material in metallurgical processes4 ,it is the lowest priced source of alkali in chemical industry4 ,pulverized limestone may be used as a filler in paints1 putty1 paper1 or rubber2 and rock wool is made by melting and blowing a limestone having a suitable chemical composition4 ,two formations develop a 8spongy0 appearance 78sponge rock0 or 8sponge limestone07 upon weathering and are utilized abundantly in the eastern part of the state for rock gardens and for ornamental and decorative stone4 ,many tons of limestone are used each year in ,missouri as a soil fertilizer because it neutralizes acidity1 coagulates the clay1 furnishes calcium to the plants by way of the colloidal clay1 and frees other chemical elements so that they become available to the plants4 ,no doubt rocks other than limestone will be crushed and added to the soil in the future1 but today our attention is focussed chiefly on limestone and dolomite4 ,the value of a limestone quarry for agricultural purposes depends upon availability1 amount of overburden1 purity of the stone1 ease of crushing1 and size of deposit4 ,for instance1 a stone of #ij purity1 which is close at hand1 will probably be more valuable than one of #ih purity which must be hauled fifteen miles4 ,bare hillsides or creek banks where a crusher can be set up to handle the stone without extra lifting are preferable for quarry sites4 ,usually the overburden is less in such an exposed face4 ,impurities in limestone deposits may be large chert 7flint7 nodules which can be hand-sorted out1 sand grains1 clay which settled into and onto the stone during its accumulation1 and pyrite 7fool's gold7 or other minerals of lesser importance4 ,clay impurities simply act as useless extra weight which must be handled4 ,sand grains1 however1 are hard1 and will abrade and wear out crushing equipment4 ,chert and fine-grained silica likewise are harder than steel and will wear a crusher excessively4 ,pure limestone 7calcite or dolomite mineral7 has a hardness less than that of steel and will only polish or wear the metal slightly4 ,illustration3 ,typical1 intermittently-operated1 farm limestone quarry near ,north ,kansas ,city4 ,it will probably pay to give some thought to this matter of crushing when selecting a quarry site for agricultural limestone4 ,the several beds of stone available should be tested not only for amount1 but kinds of impurities4 ,samples sent in for testing must be representative of the rocks under consideration or the analytical results are meaningless4 ,the writer does not believe this point can be over-emphasized4 ,time after time he has seen samples taken of geological deposits for testing which no more represented the deposits than a bantam rooster picked out of a chicken pen would represent the egg-laying or weight-production possibilities of the flock of ,plymouth ,rock hens4 ,if five layers or beds of stone are to be properly tested1 then five samples must be taken1 one broken from each layer of solid rock in place4 ,the five layers may have the same color1 or look much the same1 but fine grains of sand1 hardly visible without magnification1 may be abundant in some layers and not in others4 ,if circumstances do not permit having five different tests made1 but allow only one sample to be run1 then specimens should be taken from all five beds1 their sizes being in proportion to the relative amounts expected to be quarried from each bed1 and all five specimens sent to the analyst1 who can crush and mix them4 ,a single grab sample taken from loose rock on a hillside1 in expectation that it will represent the rocks inside1 depends as much on luck as betting on the weather next #dth of ,july1 a year hence4 ,the chemist who analyzes the limestone for calcium can usually report on the kind of impurity if he will take the time to do it4 8,cotton ,rock0 ,limestone 8,cotton rock0 refers to a white to slightly gray or buff variety of limestone which has a 8soft01 somewhat chalky and porous appearance that is suggestive of cotton4 ,missouri 8cotton rock0 is usually dolomitic4 ,although the term 8cotton rock0 has no standing in a technical sense1 its fairly wide use indicates that the name has descriptive value4 ,marble ,marble1 in a scientific sense1 is a metamorphic rock and does not occur as such in ,missouri4 ,however1 marble has been used as a name in commercial trade to refer to a crystalline1 fairly pure limestone1 which possesses most of the useful qualities of true marble4 ,in that sense the 8marbles0 quarried near ,ozora and ,carthage1 ,missouri1 are very excellent stone4 ,no doubt some recrystallization has occurred in connection with the faulting in the ,ozora region1 and this may be interpreted as mild metamorphism4 ,the ,carthage 8marble0 is quarried from beds of limestone well developed for structural purposes4 ,these 8marbles0 effervesce in acid1 of course1 just as described for limestone4 ,in this connection it is interesting to note that the polish on limestone or marble is not durable where exposed to the weather in the same sense as is the polish on granite4 ,because limestone and marble are softer than granite they may be cut and polished at lower cost1 but because of their ease of attack by acid1 water1 and abrasion they soon become dull when used as an exterior stone4 ,for interior decoration they are excellent1 of course4 ,granite contains hard minerals which happen not to be attacked appreciably by dilute acids1 and therefore it retains a polish for a long time even where exposed to the weather4 ,cave ,onyx and ,deposits ,the stalactites 7rock icicles7 hanging from cave ceilings1 stalagmites built up from the floors1 and other drip stone deposits of caves are largely calcite1 the mineral of limestone4 ,again1 this can be recognized by the limestone acid test 7effervescence1 see limestone74 ,cave onyx may be banded like agate4 ,it is then commonly called ,mexican onyx4 ,the name travertine has also been applied to such deposits from water4 ,travertine ,travertine is a general name for calcium carbonate deposits of varying size1 shape1 color1 texture1 and purity which originate largely through evaporation of spring or surface water4 ,its composition of calcium carbonate1 calcite mineral1 is easily confirmed by effervescence in acid1 like limestone4 ,calcite ,calcite 7sometimes called 8tiff0 locally in south-western ,missouri71 the essential mineral in limestone1 can be recognized by several definite characteristics3 #a4 ,it bubbles1 8fizzes10 or effervesces in dilute acid4 ,see page #aa4 #b4 ,it is easily scratched with a knife4 #c4 ,it breaks or cleaves into rhombohedral shapes1 of which at least one flat1 glistening side is visible on every individual grain in the broken surface of limestone4 #d4 ,it has a glassy luster on crystal and cleavage faces4 #e4 ,it crystallizes into six-sided crystal forms1 which can be differentiated from quartz 7also six-sided7 by tests 7#a7 and 7#b7 above4 ,the one single test of calcite which is most diagnostic1 and which appeals to most persons1 is number one above1 effervescence of the solid lump in dilute acid4 ,the bubbles are filled by carbon dioxide gas which comes from1 and is freed from1 the calcite by the reaction of it with the acid4 ,calcite is calcium carbonate1 ,ca,c,o4 ,illustration3 ,a small calcite crystal from the ,joplin region4 ,many ,missourians have not realized that the ordinary1 everyday limestone 7fine to coarse granular71 which is so abundant here1 is composed of a mineral--calcite which makes up the grains4 ,the strikingly beautiful calcite crystals 7displayed in museums7 derived from the calcite crystal caves found in some mines in the ,joplin district are accepted without question as mineral specimens of calcite1 but the idea that all of the commonplace glistening grains in the local limestone are also mineral grains is a new thought to most persons4 ,a pure limestone is composed entirely of calcite4 ,even impure limestones which contain subordinate amounts of quartz sand1 chert1 clay1 or iron oxide are in the main also calcite4 ,dolomite and dolomitic limestones contain the mineral dolomite4 ,the mineral of ordinary marble is calcite2 dolomite marble contains dolomite4 ,the cementing material in sandstone and a common accessory mineral in shale are calcite4 ,it is truly a wide-spread and abundant mineral4 ,even the lime deposit in the bottom of the tea-kettle1 the water heater1 boiler1 or automobile cooling system is calcite1 or aragonite1 a twin brother to calcite4 ,the use of calcite in the form of limestone is treated under limestone4 ,as for the use of large calcite crystals1 they are sold as ornaments and curiosities4 ,visitors to the ,missouri ,state ,fair may recall the exhibit of a beautiful1 reconstructed crystal cave which was lined with large calcite crystals4 ,calcite crystals have been shipped in car-load lots to beautify grottos1 notably some in ,iowa and ,illinois1 and are displayed in almost all prominent museums4 ,water-white 7clear71 optical-quality calcite crystals1 which command a high price1 are relatively rare and have not been found in ,missouri4 ,the optical property of calcite which accounts for its high value is its ability to separate1 or refract1 every single ray of light passing through it into two widely separated1 easily distinguishable rays1 hence doubling their number4 ,this is called double refraction1 and is shown by the double image of an object viewed through the calcite4 ,instruments which polarize light may contain calcite crystals4 ,the artificial product1 8,polaroid01 is used for a similar purpose4 ,illustration3 ,calcite cleavage rhomb1 characteristic rhombohedral shape4 ,note the double image due to high double refraction of calcite4 ,dolomite ,dolomite mineral occurs in ,missouri as a constituent of dolomitic limestone or as a vein and cavity filling in the rocks of the ,joplin mining district and as a lining in cavities in the dolomitic limestones of the southern and eastern parts of the state4 ,dolomite when powdered 7by scraping the surface of the specimen1 for dolomite is softer than steel or glass7 effervesces freely in cold dilute hydrochloric 7muriatic7 acid1 but the lump dolomite effervesces very slowly1 if at all4 ,calcite effervesces freely in the lump with cold dilute acid4 ,this acid test is the one certain test for dolomite1 and works with the thick-bedded formations as well as with the showy1 crystal-faced material from veins4 ,see page #aa4 ,dolomite crystals have a pearly luster and are usually pale pink in the ,joplin district4 ,their faces are commonly curved but where broken show glistening to pearly cleavage faces4 ,these properties assume more significance in mineral determination as one becomes familiar with mineral collections1 but the non-technical person can rely on the acid test4 ,illustration3 ,typical dolomite crystals from ,joplin region4 ,with the above information in mind1 one may proceed with certainty to identify a layer of dolomite from a quarry or hillside1 or a crystal of it in a hand specimen4 ,first1 determine that it is scratched readily with a knife blade or iron nail4 ,anything too hard to be scratched by steel is neither calcite nor dolomite4 ,second1 scrape a small mound of powder on the lump specimens4 ,third1 apply one or two drops of cold dilute acid to the lump near the powder and allow the acid to run into the powder4 ,if the lump effervesces freely the specimen is calcite mineral or limestone rock4 ,if the lump does not effervesce freely but the powder does1 it is dolomite mineral or dolomite rock1 dolomitic limestone4 ,if neither lump nor powder effervesce it is neither calcite 7ordinary limestone7 nor dolomite 7dolomitic limestone74 ,in the latter case1 it may be gypsum1 barite1 ,shale1 weathered chert1 clay1 or fire clay1 or other rock4 ,the composition of dolomite is calcium-magnesium carbonate1 ,ca,mg7,,co71 and when pure runs about #ed per cent calcium carbonate and #de per cent magnesium carbonate4 ,however1 dolomite is not a mechanical mixture of the two carbonates2 it is a single crystalline compound wherein the calcium and magnesium are securely interlocked within the arrangement of the atoms4 ,for that reason1 the extraction of magnesium metal or other magnesium compounds from dolomite is so difficult and costly that other magnesium minerals1 although not nearly so abundant and accessible to industry as dolomite1 have been processed to obtain the lightweight metal magnesium4 ,the thick beds of ,missouri dolomitic limestone 7and some fairly pure dolomite7 have been used chiefly as agricultural stone for soil sweetening1 for building stone1 gravel1 and other purposes to which rough stone is put4 ,shale ,illustration3 ,shale bluff at a strip mine near ,columbia4 ,shale is a compressed1 and layered or laminated clay or mud rock4 ,consequently it will return to mud if it is wetted with water and rubbed4 ,this may serve as a test for shale4 ,it may occur in thick layers or formations1 five1 ten to fifty or more feet in thickness1 and it ranges downward to paper-thin partings between beds of limestone4 ,it is also commonly associated with coal beds4 ,the color of shale varies from light gray to black1 or it may be tan1 yellow1 red1 rust1 purplish1 or green4 ,it is platy1 and these thin plates or laminae1 piled on each other1 make up the shale bed4 ,illustration3 ,hand specimen of shale shown in preceding picture4 ,note the characteristic thin layering or lamination4 ,some shales are hard1 tough1 and strong enough to serve as temporary mine roofs4 ,hard shales are sometimes called 8slate0 but this name is technically incorrect4 ,true slate is a metamorphic rock1 composed chiefly of the mineral mica in very fine flakes1 and will resist the action of water 7weathering7 for a long time4 ,therefore1 it is a good roofing material for buildings1 whereas shale is composed chiefly of clay minerals1 and despite the strength and compactness of the more 8slaty0 varieties soon disintegrates in water4 ,missouri 8slaty0 shale would not serve as satisfactory roofing material4 ,the red 8burned0 shale found on burned-out coal mine dumps is called 8shale0 locally4 ,it is1 of course1 shale which has been fired more or less to the condition of building brick by the hot burning waste coal4 ,the same original shale could be crushed1 molded into brick1 8burned0 in a kiln1 and become a satisfactory building brick4 ,the 8burned shale0 of the coal mine dumps is used in many places as a drive-way covering4 8,soapstone0 is a name applied by some persons to some soft1 slippery to greasy shales1 but this name is incorrect in a technical sense4 ,true soapstone is a metamorphic rock 7shale is sedimentary7 which is composed chiefly of the mineral talc4 ,soapstone occurs abundantly in certain parts of the ,appalachian ,mountains but is exceedingly sparse in ,missouri4 ,the chief commercial uses of shale are in the manufacture of common brick1 building brick1 building tile1 drain tile1 sewer pipe1 ,portland cement1 and other ceramic products4 ,many shale beds and occurrences are technically suitable for these uses but have no real commercial value because other necessary factors are lacking4 ,in order to make brick1 tile1 or cement there must be sufficient fuel available at low cost1 low-priced bulk transportation of the raw and finished products1 available labor1 capital for the erection of a plant1 and above all a large near-by1 dependable market for the manufactured product4 ,the value of a shale deposit1 therefore1 depends as much upon outside conditions as upon the properties of the rock 7shale7 itself4 ,the shales of ,missouri were formed from deposits of mud that settled out in sea water which in the past covered this state4 ,fossil remains of sea-living organisms which are preserved in the shale give evidence of the marine conditions once existent here4 ,like the muds that are accumulating along the ,atlantic coast and in the ,gulf of ,mexico1 where the ,mississippi ,river is discharging its load of silt and clay1 so did mud form layers on the bottom of geologically ancient interior seas4 ,in some cases sand was later washed in and covered the mud2 in other cases limestone-forming material 7like off the coast of ,florida today7 was deposited on top of the mud4 ,the weight of the overlying beds and the slow movement which raised the sea bottom up to land squeezed out the excess water1 compressed and compacted the muds into thin layers1 and brought about the shale rock which is exposed to us today4 ,illustration3 ,soft1 easily eroded bed of shale between two more resistant beds of limestone near ,columbia4 ,black muds1 rich in humus and other organic material1 formed black shales2 red and yellow clays colored by red and yellow iron oxides 7iron rusts7 formed red and yellow shales2 and sandy muds were compacted into gritty1 sandy shales4 ,all of them were derived from eroding land and soils just as today our eroding soils contribute to the formation of more shale now in the long1 slow process of formation4 ,the chemical composition of an average shale is not simple1 as is shown by the subjoined composite analyses of sedimentary rocks taken from ,u4 ,s4 ,geological ,survey ,professional ,paper ,no4 #abg4 #gh shales #bec sandstones #cde limestones ,si,o #eh4aa #gh4ca #e4ai ,al,o #ae4dj #d4gf 4#ha ,fe,o #d4jb #a4jh 4#ed ,fe,o #b4de 4#cj ,mn,o #b4dd #a4af #g4hi ,ca,o #c4aj #e4ej #db4eg ,na,o #a4cj 4#de 4#je ,k,o #c4bd #a4cb 4#cc ,h,o #c4ff #a4cb 4#ef ,h,o- #a4cc 4#ca 4#ba ,,co #b4fc #e4jd #da4ed ,ti,o 4#fe 4#be 4#jf ,p,o 4#ag 4#jh 4#jd ,,so 4#fe 4#jg 4#je ,organic carbon 4#hj -- -- 7#ajj47 7#ajj47 approx4 7#ajj47 ,many persons upon learning that average shale1 and even 8clay dirt10 may contain #ae alumina1 ,al,o 7equivalent to almost #h metallic aluminum71 become thoughtlessly and erroneously enthusiastic about aluminum ore possibilities on their farms or properties4 ,the aluminum is there all right1 but it is so securely combined with silica and other elements that the cost of extraction is now greater than the price of aluminum obtained from less abundant ores4 ,until chemists find a method of extraction of the metal from ordinary clay or shale that can be carried out at considerably less expense than is now possible1 the vast quantities of clay and shale on the earth's surface must be considered a distant reserve of a prohibitively high cost aluminum4 ,missouri possesses a little bauxitic clay in the southeastern part of the state but unfortunately does not contain deposits of high grade bauxite1 the chief ore of aluminum1 and so does not contribute to the aluminum production of the ,united ,states 7see the discussion under ,,diaspore ,,clay74 ,arkansas is a leading producer of bauxite1 but the geological conditions present in that bauxite locality are so different from ,missouri geology that little hope is held for finding bauxite in ,missouri1 except possibly in the extreme southeastern part4 ,fire ,clay ,fire clay resembles shale in that it is also a clayey rock and becomes muddy upon wetting and rubbing4 ,it differs from shale at sight in that it 7fire clay7 is not laminated like shale1 but occurs instead in a massive structure which is relatively uniform throughout4 ,fire clay fractures naturally into blocky or irregular fragments ranging in size from boulders to rough flakes1 whereas shale weathers into layered1 platy chips4 ,shales are commonly buff1 yellow1 reddish1 greenish1 or brown in addition to gray in color1 whereas good useable fire clay predominates in white1 cream1 and gray to almost black 7if much organic matter is contained in it74 ,shale is ordinarily gritty with hard sand particles1 but most good ,missouri fire clay contains only a small amount of sand4 ,of course1 fire clay may grade into sandstone through a sandy clay phase1 but this part would not be confused with a layered1 gritty shale4 ,the really determining characteristic of fire clay is its resistance to melting under high temperature4 ,the most positive test for this property is to heat the fire clay to a white heat in comparison with standard preparations 7,pyrometric ,test ,cones7 whose fusion temperatures are known4 ,most of ,missouri fire clay will withstand a clean oxidizing heat of over #cjjj ,fahrenheit without melting4 ,clay minerals originate1 in general1 from the weathering of previously existing silicate rocks and have therefore been called1 on occasions1 8rotted rocks40 ,the writer has long insisted that clays1 particularly fire clays1 should be thought of instead as purified or refined rocks4 ,the original silicate rocks and minerals1 which were rich in constituents melting at low temperatures1 have been soaked1 leached1 and washed by chemically active ground water and rain water until many of the undesirable elements have been carried away1 leaving a refined material which we use and know as fire clay4 ,missouri possesses one of the largest reserves of finest quality fire clay in the world4 ,special bulletins on ,missouri fire clay are published by the ,state ,geologist1 ,rolla1 ,missouri1 and may be obtained from his office4 ,illustration3 ,plastic fire clay4 ,shows typical break and naturally polished slicken-sided surfaces4 ,from ,mexico1 ,missouri4 ,illustration3 ,typical break4 ,persons who have undeveloped fire clay deposits on their property frequently ask advice on whom to contact and how to arrange for sale of their fire clay1 with the expectation of a fair return and fair treatment4 ,the writer recommends in such cases that the owner of the clay dig into his deposit to obtain a fresh1 clean1 representative specimen of his fire clay 7about one pound7 and send it to one or more of the large substantial fire brick or refractories companies operating in ,missouri4 ,obviously the company located nearest the deposit1 or with the lowest-cost shipping facilities1 will be in a favored position to purchase the clay4 ,if the individual is skeptical about the trustworthiness of the company's report1 he may send opposite parts of the sample lumps to competitive companies4 ,of course1 the individual may have his clay tested by an independent laboratory at his own expense1 but this is ordinarily a useless1 costly experience because a company will duplicate those tests in its own laboratory before purchasing the clay4 ,if the refractories companies find the clay useful to them they will proceed with negotiations4 ,if the clay is of inferior quality or if it is not needed by the particular company at that time1 even though of acceptable quality1 usually the company will return a truthful report at no cost to the clay owner4 ,the same general advice is given in regard to the development of any mineral deposit which the holder may have4 ,the caution about obtaining a representative sample is especially to be emphasized4 ,it applies to the metallic ores1 mineral water1 and common rock as well as to fire clay4 ,plastic ,fire ,clay ,plastic fire clay forms a sticky1 soft mass when wetted and kneaded with water1 and will bond together other clays or rocks4 ,large plastic fire clay deposits occur in ,audrain1 ,callaway1 and ,st4 ,louis counties1 and lesser quantities are known in ,boone1 ,osage1 ,gasconade1 and ,phelps counties4 ,the larger deposits assume a blanket shape with a highly irregular lower surface4 ,flint ,fire ,clay ,flint fire clay is very fine-grained1 smooth or slick1 and breaks with a shell-like 7conchoidal7 fracture4 ,it varies in color from white to black1 but most flint fire clay mined is near to white4 ,it is relatively non-plastic--that is1 does not readily slake or form a sticky mass when worked a little in water4 ,in fact1 flint fire clay has been used locally as road surfacing because it does not become very muddy and sticky4 ,of course1 it is inferior to black-top or concrete road surfaces and has too high a commercial value now to be used extensively as road metal4 ,a hard1 white variety of flint fire clay which breaks with numerous conchoidal fractures in appropriate shaped fragments has been called locally 8pop-corn flint40 ,this clay1 and other sand-free flint clay1 when crushed between one's teeth 8goes to water0 in the mouth4 ,many clay miners use the chewing test to establish the freedom of their clays from gritty sand1 which renders flint clay inferior in quality4 ,illustration3 ,flint fire clay showing typical 8slick break0 and conchoidal fracture1 from near ,new ,florence4 ,flint fire clays occur geologically in old land depressions and in roughly funnel-shaped pits surrounded by an enclosing layer of sandstone1 the whole lying within limestone country rock4 ,the most prominent flint fire clay deposits are found in ,callaway1 ,warren1 ,lincoln1 ,osage1 ,gasconade1 ,maries1 ,franklin1 and ,phelps counties4 ,diaspore ,clay ,diaspore clay is a harsh1 usually porous1 earthy type of clay which has been found in ,warren1 ,osage1 ,gasconade1 ,maries1 ,franklin1 ,phelps1 and ,crawford counties in ,missouri4 ,some diaspore clay is mealy1 or finely granular1 some is chalky to compact1 and much of it is more or less oolitic4 ,oolites 7oolitic structure7 are small rounded bodies varying in size from about bird shot to ,,bb shot size1 and those in diaspore may be solid or hollow4 ,their hollow structure contributes to the porous condition in diaspore clay4 ,see page #bi4 ,it is almost impossible to write a description of diaspore clay which can be used to determine it because the clay has so few individual characteristics4 ,a person familiar with diaspore clay1 however1 can recognize it at a glance4 ,probably diaspore clay will not be found outside the counties listed above1 and within those counties many persons know the clay from contact with the commercial production of it4 ,illustration3 ,diaspore clay1 over #gj alumina1 from near ,belle4 ,diaspore clay occurs in old sink-hole1 funnel-shaped pits which formed in the dolomite 7limestone7 underlying that region4 ,a sandstone layer which lines the pit and commonly stands somewhat above the level of the clay because of the sandstones superior resistance to weathering is known as the 8rim rock0 of the pit4 ,the diaspore clay may be thought of as an extra-refined type of fire clay from which silica has been leached during prolonged solution in swamps and ground water and the more stable alumina 7,al,o7 left behind as the refined product4 ,pits in the diaspore region may contain from a few truck loads of clay to over #ej1jjj tons of it1 but a pit which produces #aj1jjj tons of good clay is a valuable and not very common deposit4 ,a small fortune falls to the landowner who finds a large diaspore deposit 7pit7 on his farm1 for royalty rates at this time are not less than #a4jj per ton for first grade1 #gj ,al,o clay4 ,because of the high value of diaspore1 a highly competitive prospecting1 leasing1 mining1 and brokerage business has developed in the diaspore region4 ,practically all of the thrills1 hopes1 disappointments1 and good fortunes that are associated with oil booms are found in this business and clay area2 clay pits are only smaller in scale than wild oil gushers4 ,clay scouts work in secret1 mining leases are contested in court1 rumors fly fast in ,english1 ,german1 and ,german-,swiss over the country telephones1 prospecting results may be hidden1 personal pressure may be brought to influence a deal1 and speedy salesmanship is employed when an exciting find is in the offing4 ,when the legends1 traditions1 and facts of the diaspore region are collected and recorded1 an interesting and essential part of ,missouri history will have been written4 ,missouri has the only locality in the entire world where relatively pure diaspore clay is now mined in commercial quantities4 ,because of its extreme resistance to fusion under very high temperatures1 diaspore has been called the 8aristocrat of fire clays40 ,diaspore contains a higher percentage of aluminum than does bauxite1 the chief ore of aluminum1 but because of diaspore's extremely refractory nature it is less easily reduced to aluminum metal than is bauxite1 and therefore finds a more specialized use in the manufacture of refractory and super-refractory brick and tile which may even be used in furnaces to calcine aluminum ore4 ,where resistance to very high temperature has been required1 diaspore super fire brick has been remarkably useful4 ,burley ,clay ,illustration3 ,burley clay4 ,note the oolitic structure1 the 8burls40 ,from a diaspore pit near ,swiss4 ,burley clay is a fire clay intermediate in alumina content between flint clay and first quality diaspore4 ,it takes its name from the oolites 7rounded pellets of diaspore7 which are scattered through a flint clay base and which were called 8burls0 by the early clay miners4 ,as the relative number of diaspore oolites increase1 an otherwise flint clay becomes burley-flint1 then typical burley1 and finally grades into second quality and first quality diaspore4 ,clay in any stage of the variation may be found in some part of the diaspore region or pits4 ,most of the remarks written on diaspore apply as well to burley clay4 ,sandstone ,sandstone is a rock made of sand-size particles more or less well cemented4 ,it is recognized by the grains of sand which are dislodged or scratched loose when the rock is broken1 or when scraped with a piece of steel or another hard rock4 ,the old-fashioned grindstone is a sandstone nicely cemented by nature4 ,illustration3 ,sandstone bluff near mine entrance1 ,crystal ,city4 7,photo courtesy of ,pittsburgh ,plate ,glass ,company47 ,sandstone occurs in thin layers to thick massive beds and deposits which may exceed fifty feet in thickness4 ,in addition to possessing horizontal bedding and parallel bedding planes1 some sandstone displays beautiful1 intricate cross-bedding or cross-lamination4 ,the grains of sand composing the stone may be either angular or rounded4 ,they may sparkle in the light from reflections from their crystal faces1 or they may have dull1 frosted surfaces4 ,sandstones are ordinarily nearly white in color except where the grains are covered with coatings of yellow or red iron oxide 7rust74 ,illustration3 ,cross-bedding in sandstone north of ,fredericktown4 ,illustration3 ,sandstone in hand specimen4 ,magnification #dx4 ,illustration3 ,quartz sand grains4 ,magnification #bax4 ,the grains themselves are predominantly particles of the mineral quartz1 although any rock or mineral of sand size may be present in sandstone4 ,the quartz 7see discussion of quartz on page #da7 may have been derived from pre-existing sandstones or more directly from granite1 porphyry1 or other igneous rocks in which quartz crystallized when the hot liquid rock solidified4 ,today quartz grains which are weathering out of igneous rocks and sandstones are being carried by the ,missouri river and tributaries to the ,mississippi river and thence to the ocean1 where extensive deposits of sand are accumulating1 probably destined to become widespread beds of sandstone4 ,the grains of sand may be broken and become angular during their long trip to the ocean1 or they may become rounded by rubbing against each other4 ,if they exist in sand dunes1 blown about by the wind before being cemented into rock1 the grains usually become somewhat rounded4 ,even after sandstones are buried beneath other rocks1 silica1 which is carried in solution by ground waters percolating through the sandstone1 may crystallize out on the sand grains and restore some brilliant1 angular crystal faces to the otherwise rounded grains4 ,cementation of loose sand to more or less firm sandstone is due to the presence of clay1 iron oxides1 or calcite 7mineral of limestone7 which may be deposited with the sand4 ,all of these cements are softer and weaker than quartz1 thereby being broken first and freeing the harder quartz when the rock is scratched or crushed4 ,a variety of very hard sandstone called quartzite is one that is so strongly cemented that it breaks through the sand grains instead of around them as is the case with ordinary sandstone4 ,this condition is brought about by their being cemented with silica 7chemically the same as quartz71 which makes for essentially uniform hardness throughout the rock4 ,quartzites are1 as previously noted1 extremely hard1 and resist abrasion and chemical weathering4 ,reddish quartzite boulders occur rather abundantly north of the ,missouri ,river in the glacial clay1 sand1 and gravel which overlie the sedimentary rocks that form the bed rock or country rock there4 ,locally1 the hard1 red quartzite boulders may be called 8red niggerheads01 although the term 8niggerhead0 is more often applied to black or dark greenish black boulders of basalt 7see page #dh7 also present in the glacial drift4 ,it is to be recalled that the distinguishing hardness of quartzite is due to the hardness of the quartz grains plus the equal hardness of the silica cement4 ,asphaltic sandstone is a sandstone impregnated with a bituminous residue from the evaporation of petroleum which once occupied the pores of the rock4 ,it has been reported from more than a dozen counties in western ,missouri1 but the most extensive deposits are probably in ,barton1 ,vernon1 and ,lafayette counties4 ,attention has been directed to the origin of sandstones from ocean deposits of sand and from sand dunes1 but it should be recognized also that river channels and stream valleys which contain deposits of sand 7such as those on floodplains1 river bottoms1 and sand bars7 may be covered1 and the sand consolidated to sandstone4 ,many years ago1 even long ago geologically1 a large river1 almost comparable in size to the ,missouri river1 occupied a channel which is now represented by a long narrow sandstone deposit extending from a little north of ,clinton through ,warrensburg to ,lexington and then east through ,moberly almost to ,paris4 ,smaller channel sandstones are abundant in other areas in ,missouri4 ,the sandstones of the so-called ,roubidoux formation1 which occurs in south central ,missouri1 commonly show well-preserved ripple marks on the rock slabs4 ,these marks were formed exactly as their name suggests--in sand which was thrown into ripples by the shallow water in which it accumulated and was covered and cemented so as to retain the ripple forms4 ,illustration3 ,ripple marks in limy sandstone4 ,sandstone is used for building stone1 walks1 grindstones1 furnace linings1 and rock gardens4 ,large quantities are mined each year near ,pacific1 ,festus and ,crystal ,city1 ,klondike1 and ,hermann1 for the manufacture of glass and other uses4 ,common glass is a cooled melt of relatively pure silica sand1 soda ash1 and lime4 ,asphaltic sandstone is used in road building4 ,sand-lime brick are made of sand4 ,sand is used as a molding material for metal castings1 a parting substance between brick in kilns1 and in large quantities in concrete and mortar mixtures4 ,chert1 ,flint ,the names chert and flint have in some regions been used for the same hard1 fine-grained rock found so abundantly in ,missouri1 but correct usage employs chert for the white and gray varieties1 and flint for the black variety4 ,flint may be thought of as slightly impure chert1 a chert which is colored black by a small amount of pigment1 usually fine carbon1 or perhaps iron sulphide1 scattered through it like fine dust4 ,illustration3 ,chert1 fossiliferous and slightly speckled4 ,note typical sharp edges1 smooth surfaces1 and conchoidal fracture4 ,from near ,columbia4 ,chert is characterized by being harder than glass1 brittle1 very fine-grained1 and by breaking with a smooth1 rounded or hollowed clam shell-like 7conchoidal7 fracture and sharp edges4 ,it was used by ,indians to make arrow heads4 ,it accumulates in abundance both in stream beds as gravel which has been more or less rounded by wear1 and on the hillsides within the soil and sub-soil4 ,yellow and red iron oxides may stain and penetrate weathered chert gravel so that it becomes reddish1 rusty1 tan1 yellow or brown4 ,chert remains abundant because of its extreme resistance to weathering4 ,it is so hard that stream action wears it only very slowly4 ,its chemical composition is silica1 ,si,o1 a substance which is but little affected chemically by ground water4 ,where chert has contained fine grains of calcite scattered through it1 the calcite may be removed in solution1 leaving pores1 and a zone of porous1 light weight1 tripolitic chert1 harsh to the feel and enveloping an unaltered interior 7,see ,,weathered ,,chert74 ,not uncommonly1 fossil remains of calcite which were embedded in chert have been dissolved1 leaving their hollow impressions4 ,chert in ,missouri originally occurs chiefly in limestone formations1 where it is found as nodules1 lenses1 stringers1 and irregular forms in and between the limestone beds4 ,chert and flint may be deposited directly from silica in solution1 or they may replace 7substitute for7 wood1 fossils1 or older rock where silica-bearing solutions contact and react with the replaced substance4 ,for example1 petrified wood usually is wood which has been replaced molecule by molecule with silica4 ,this statement applies equally to the brightly colored petrified wood in the ,petrified ,forest in ,arizona and to that with comparatively drab coloring in ,missouri4 ,many other siliceous fossils1 notably animal remains1 are replacements of calcite 7limestone7 by silica4 ,in anticipation that the reader may have difficulty understanding how silica may go into solution if chert 7silica7 is hardly attacked by the weathering process1 it should be explained that silica is freed in solution predominately during the weathering of complex silica-combinations1 silicates1 rather than from uncombined silica4 ,for instance1 feldspar and pyroxene from granite or gabbro weather in ground water to a soil-forming clay mineral and release some silica in solution in the ground water4 ,after this silica is redeposited in an uncombined form1 like chert1 it becomes highly insoluble4 ,an observation in regard to flint is that the metallic 8flints0 which are used to ignite gas burners or cigarette lighters are not black chert1 ,si,o4 ,instead1 they are special alloys containing rather uncommon elements which possess the useful characteristic of emitting a brilliant hot spark when harshly scratched4 ,chert is the chief source of natural gravel in ,missouri because it accumulates in stream beds and on hillsides on account of its resistance to weathering4 ,the piles of 8chats0 in the ,joplin region1 containing thousands of tons of crushed chert1 have been used in part in road surfacing material4 ,weathered ,chert ,weathered chert1 or leached chert1 is a white to gray1 or yellowish1 porous1 light-weight1 harsh to feel1 chalky-appearing rock which occurs over much of the southern half of ,missouri4 ,it does not effervesce in acid4 ,usually it occurs as a zone from a fraction of1 to more than an inch in thickness1 about a denser core of hard1 compact chert 7flint71 or makes up an entire small rock fragment or gravel4 ,illustration3 ,chert hand specimen showing quartz-lined fossil cavity in center1 compact fresh chert in interior1 and chalky-appearing weathered outside margins4 ,from near ,columbia4 ,it develops as a relatively insoluble residue left when the more soluble rock material in association has been leached away during the weathering process4 ,its composition approaches pure silica4 ,it has no established use and no commercial value4 8,kaoleen0 8,kaoleen0 is a term used locally in part of south-central ,missouri to refer to a chalky1 white to tan or buff1 porous weathered chert1 but the name should be dropped because it is unnecessary 7use weathered chert71 confusing1 and not recognized elsewhere4 ,most probably the term arose in corruption of the word kaolin1 which is the name for a true1 high-quality clay1 to which the leached and weathered chert bears a slight resemblance4 ,kaolin has the chemical composition of clay 7hydrous aluminum silicate71 whereas 8kaoleen0 is impure silica4 ,see the discussion on ,weathered ,chert4 ,tripoli ,tripoli occurs in the vicinity of ,seneca1 ,newton ,county1 ,missouri4 ,it is a light-weight1 porous1 white to creamy1 siliceous rock1 which may be scratched because of its softness4 ,tripoli represents the porous insoluble residue of an earlier rock1 which was composed of skeletal insoluble silica and interstitial soluble calcium carbonate 7calcite71 the latter having been dissolved away by ground water4 ,tripoli has a chalky appearance but is totally unlike chalk chemically4 ,tripoli is nearly pure silica1 whereas chalk is calcium carbonate4 ,any tripoli-like rock found in ,missouri outside the region of tripoli mines is likely to be a fragment of weathered chert which is described above4 ,tripoli has been used as an abrasive1 a polishing agent1 a parting material in molding sand1 and a filter rock4 ,agate ,agate is a banded variety of chert4 ,although the chemical composition of agate is ,si,o1 the same as chert1 a microscopically fibrous part of it having a waxy luster or varying in color or translucency may give the appearance to the rock that we associate with the name agate4 ,the mineral name chalcedony is given to the fibrous1 waxy material4 ,typical agates are most abundant in ,missouri in the glacial and stream gravels in the northern part of the state1 although part of the ,potosi drusy quartz and chalcedony in the southeast is also prized4 ,the large gravel pit near ,la,grange1 in the northeast1 has furnished many beautiful specimens1 not only of agate1 but also of petrified wood and fossils4 ,missouri lapidists and collectors of semi-precious stones find plenty of interesting raw material within their own state4 ,jasper ,jasper is chert which is colored red or yellowish brown by iron oxides4 ,granite ,illustration3 ,close view of a granite hand specimen4 ,feldspar predominates4 ,quartz appears dark in the photograph1 but shows glistening edges and points4 ,from ,graniteville4 ,granite is a granular 7coarse-grained7 rock which has a glassy luster and is too hard to be scratched appreciably by steel4 ,it may be white to gray1 tan1 brown1 or pink to red in color1 but pinkish to red granite predominates in ,missouri4 ,some black stone1 referred to locally as 8black granite10 is usually a variety of gabbro4 ,most ,missouri granite is coarse-grained1 so that the constituent mineral grains--quartz1 feldspar1 and 7less frequently7 mica--can be readily recognized by anyone familiar with those minerals4 ,it makes up many of the mountains and hills in ,iron1 ,madison1 and ,st4 ,francois counties and adjacent regions4 ,north of the ,missouri ,river1 or where the glacial deposits remain1 granite boulders may occur in the sandy and clayey glacial drift4 ,the mineral quartz is recognized in granite by its glistening1 oily luster1 really more brilliant than the luster of glass1 and by its curved to irregular broken surface4 ,furthermore1 the brilliant luster of quartz is not dulled by exposure to weather4 ,the mineral feldspar1 in granite1 has a glassy luster on the tiny flat cleavage faces where the individual grains are broken4 ,where weathered1 feldspar becomes dulled1 and chalky to dusty or clayey4 ,fresh feldspar may be glassy1 white1 buff1 pink1 red1 in intermediate shades in color4 ,with the mica1 it imparts most of the color to granite4 ,mica is recognized by its softness and its ability to be split very easily into tiny flakes4 ,other minerals may be found in granite under the microscope1 but they have little importance or significance4 ,illustration3 ,granite at the 8,elephant ,rocks10 ,graniteville4 ,the large boulders now rounded by weathering are remnants of a higher part of the large granite body which underlies this region4 7,photograph courtesy of ,mr4 ,noel ,hubbard74 ,granite is an intrusive igneous rock2 that is1 it solidified from a hot liquid state 7like lava7 in a large body1 beneath1 or surrounded by pre-existing rocks4 ,because of slow solidification a coarse-grained texture was developed4 ,in southeastern ,missouri where granite is now exposed at the surface 7for example1 the ,elephant ,rocks ,state ,park at ,graniteville71 that granite was covered originally by hundreds of feet of rock at the time it solidified from a liquid4 ,during the millions of years which have elapsed since the granite solidified1 its cover and the upper part of the granite have been eroded away by streams and rain after weathering to soil material4 ,in fact1 the ocean has covered the area several times during its long geological history4 ,missouri has a fine quality of granite in large quantity in southeastern ,missouri4 ,granite is used for building1 structural and monument purposes 7see discussion under marble71 for rubble stone1 rip-rap1 ballast1 gravel1 paving blocks1 crushed chicken gravel1 and for other specialized uses where favorably located4 ,chemical analyses of granite and porphry1 taken from ,missouri ,geological ,survey ,report1 ,volume ,,viii1 #ahie1 follow4 ,porphyry #f miles east ,granite #f miles east of ,ironton of ,ironton ,si,o #ga4hh #gb4ce ,al,o #ab4hh #ac4gh ,fe,o #c4je #a4hg ,fe,o #a4je #j4cf ,ca,o #a4ac #j4hg ,mg,o #j4cc #j4db ,k,o #d4df #d4di ,na,o #d4ba #d4ad ,p,o #j4ae #j4ac ,ti,o #j4bb #j4dd ,ignition loss #j4bf #j4ed ,the glacial granite boulders found in central to northern ,missouri also solidified as intrusive rock in the northern ,united ,states or in ,canada4 ,after being exposed at the surface they were picked up and carried down by the geologically recent1 continental ice sheet 7glacier7 that moved down from ,canada to across the northern half of ,missouri4 ,scratches and grooves may have been cut in some of these boulders1 or flat faces scoured and planed off as they were scraped against other hard rocks4 ,quartz gravel is usually present1 often in abundance1 in glacial deposits4 ,small specimens of native metallic copper1 which come from near ,lake ,superior1 have been found in ,missouri glacial deposits4 ,even diamonds from an unknown source in the north were carried by the ice down into the ,united ,states4 ,the history of the glaciation is a spectacular account of changes which our continent has undergone in the geological past4 ,illustration3 ,glacial scratches on boulder carried by the large glacier in northern ,missouri long ago4 ,boulder from near ,columbia4 ,quartz ,quartz is a mineral of wide-spread occurrence which is characterized by the following properties3 7#a7 it is considerably harder than glass or steel1 7#b7 it has a high luster1 glassy to oily1 7#c7 it breaks with an irregular or rough glistening fracture1 and 7#d7 it crystallizes in six-sided crystals when it grows unobstructed4 ,ordinary acids do not attack quartz1 and it is relatively unaffected by chemical weathering in ,missouri4 ,its composition is silicon dioxide1 ,si,o4 ,quartz occurs in granite as the lustrous1 partially rounded grains which constitute perhaps #bj of the rock 7feldspar makes up most of the more opaque remainder which breaks with many small flat faces71 and is recognized in the small glistening grains in the porphyry4 ,hence it is an important igneous rock-forming mineral4 ,sandstone in ,missouri is made almost entirely of quartz grains which have been broken1 worn1 and more or less rounded during their long travel history4 ,the sandstone formation quarried and mined near ,pacific and ,crystal ,city1 named the ,st4 ,peter sandstone formation1 is an outstandingly pure quartz sandstone and therefore usable in the glass industry4 ,it is obvious that quartz is an important constituent of sedimentary rocks4 ,illustration3 ,lustrous1 translucent quartz4 ,the irregular fracture and oily luster are characteristic4 ,further1 in the sedimentary dolomite formation near ,potosi1 fine to coarse quartz crystals line the surfaces of cavities and pockets in the stone4 ,this cavity coating of quartz which reflects light brilliantly from the many small crystal faces is called drusy quartz by the mineralogist1 but is locally and popularly known as 8blossom rock40 ,thousands of pounds of 8blossom rock0 are sold each year for rock gardens and various ornamental purposes4 ,in northeastern ,missouri quartz crystals line the hollow1 more or less spherical bodies called ,geodes1 which vary in size from small nuts to melons1 and weather out of the so-called ,warsaw formation4 ,other types of hollow cavities in many ,missouri rocks may contain quartz growing inward from their walls4 ,missouri chert is composed primarily of quartz in microscopically fine grains2 likewise1 agate and petrified wood may contain abundant quartz4 ,other varieties are rock crystal1 rose quartz1 amethyst1 false topaz1 bloodstone1 carnelian1 and onyx4 ,quartz crystallized in an igneous rock as the hot fluid cooled through its 8freezing0 temperature interval1 which was probably not below #ajjj;,f4 ,in the cases of the quartz in geodes1 the drusy quartz1 or that in cavities within petrified wood1 quartz crystals grew from ground water solutions which must have carried very low concentrations of silica in solution1 and whose temperatures did not depart far from that of rocks buried at various depths today4 ,although quartz is a very common and abundant mineral1 our specific knowledge about its transport and deposition is surprisingly meager4 ,illustration3 ,quartz crystal cluster4 ,crystals are six-sided4 ,from ,arkansas4 ,quartz crystals are used in large quantities in radio apparatus where it is necessary to maintain very close control on the tuning of a circuit4 ,this use requires quartz of highest quality and crystals above minimum size1 which have never been found in ,missouri and probably are not present4 ,silica production from this state is in its sandstone1 tripoli1 chert chats1 and rock garden ornamental stone4 ,feldspar ,feldspar is a white to pink or red mineral having a glassy luster on its flat broken surfaces 7cleavage faces74 ,it will scratch window glass4 ,it is the most abundant mineral in granite and usually controls the color of that rock2 for example1 the red granite at ,graniteville contains red feldspar1 and the pink-gray granite in the ,knoblick region has feldspar of those colors4 ,small bodies or bands of very coarse feldspar1 quartz1 and mica 7pegmatite dikes7 which cut the granite may contain crystals of feldspar large enough to be recovered as small1 hand specimens1 but otherwise it does not occur in coarse fragments4 ,the recognizable crystals1 or phenocrysts1 in the porphyry are mainly feldspar4 ,illustration3 ,a large piece of feldspar showing cleavage surfaces4 ,feldspar is really a family name for a group of several minerals1 all of which are crystallized in the igneous rocks4 ,the potassium 7potash7-containing varieties1 named orthoclase and microcline1 occur in the granite and porphyry1 whereas plagioclase1 a calcium-sodium 7lime-soda7 feldspar is in gabbro1 diabase1 and basalt4 ,plagioclase commonly has a thin1 lath shape1 is a shade of gray1 and makes up the lighter colored part of the greenish to dark gray igneous rocks4 ,further differences between it and orthoclase may interest the mineralogist but are of little concern to the non-technical person4 ,pulverized feldspars are used extensively in the ceramic industries1 but ,missouri does not have any productive deposits4 ,under natural1 long-time weathering processes feldspar usually decomposes to clay which may be used technically1 but the usual fate of it is soil formation4 ,mica ,mica1 incorrectly called isinglass1 is an elastic1 fairly soft1 platy mineral1 which may be split into flakes of paper thinness4 ,the relatively clear variety is called muscovite1 and the brownish black to black variety is biotite1 both being members of the mica family4 ,they may occur in ,missouri in small grains in the igneous rocks1 except that muscovite may be present in sandstone1 where it was deposited along with the quartz sand4 ,mica is used chiefly as insulating material in the electrical industry where large sheets are required4 ,another use is as window or chimney material in stoves or lanterns4 ,missouri has no mica which is satisfactory for these purposes4 ,porphyry1 ,rhyolite1 ,rhyolite ,porphyry ,porphyry and granite are the two most abundant igneous rocks in southeastern ,missouri 7,iron1 ,madison1 and ,st4 ,francois counties1 and adjacent country74 ,the porphyry there is a compact1 very fine-grained1 almost glassy1 hard1 brittle rock that varies in color from light gray through pink and red to dark purplish red and almost black4 ,it always breaks with a horny1 flinty fracture4 ,small mineral crystals of glistening quartz and usually reddish feldspar are generally scattered throughout the dense background 7groundmass74 ,the crystals are commonly about one-sixteenth of an inch in cross section and ordinarily constitute from about ten to twenty per cent of the rock4 ,other names1 somewhat more specific than simple porphyry1 which are applied technically to certain phases of the rock are rhyolite1 and rhyolite porphyry4 ,illustration3 ,rhyolite porphyry showing phenocrysts 7light 8freckles07 of quartz and feldspar4 ,from near ,ironton4 ,the porphyry of southeastern ,missouri is igneous rock which in the main poured out as lava flows1 millions of years ago4 ,volcanic dust or 8ash0 was erupted during the same period1 and layers of it1 now strongly cemented1 are found in association with the flow rock4 ,the ,missouri rhyolite porphyry has about the same chemical composition 7see page #dj7 as ,missouri granite1 but whereas granite is coarse-grained1 the porphyry has an extremely fine-grained to almost glassy ground-mass4 ,this difference in texture 7grain size7 is due to the difference in rate of solidification4 ,the porphyry lava flows chilled and solidified very rapidly1 thereby freezing the liquid to glassy and extremely fine-grained rock1 except for the scattered larger crystals 7phenocrysts7 which had developed prior to eruption4 ,granite1 on the other hand1 solidified very slowly under a thick cover of rock which acted as a heat insulator1 and during the long time of solidification large or coarse grains of minerals could grow and develop by crystallization so that a coarse-textured rock 7granite7 was formed4 ,the relative ages of the ,missouri igneous rocks are of interest to geologists and to most persons who recognize the different types within a small area4 ,it has been found that the prophyry was invaded by the granitic liquid1 that both the porphyry and granite were cracked after solidification1 and that liquid basalt rose and filled the cracks4 ,hence the porphyry is the oldest1 the granite next in age1 and the basalt is youngest4 ,in fact1 it may be mentioned in passing that some basalt and allied dikes have been found cutting through the sedimentary sandstone1 shale1 and limestone which overlie the igneous granite and porphyry and are much younger4 ,missouri porphyry has little use or value other than of bulk or crushed stone4 ,basalt ,basalt is a fine-grained1 dark-gray1 dark-green1 or greenish-black rock which is hard enough to be scratched with difficulty by steel4 ,it originated by the solidification of lava4 ,today1 basalt rock is forming where lava at the ,hawaiian volcanoes solidifies4 ,the relatively small amount of basalt in southeastern ,missouri solidified mostly in cracks within other rocks through which it rose4 ,those occurrences--that is1 fillings in nearly vertical cracks--are called dikes4 ,the basalt dikes in southeastern ,missouri have been exposed by the weathering and erosion of rocks which previously covered them4 ,illustration3 ,a dark dike of basalt in granite near ,silver ,mines4 ,in northern ,missouri1 boulders of basalt may be found in deposits of glacial clay1 sand1 and gravel 7glacial drift71 where they were left after the melting of the great ice sheet which brought the basalt down from ancient dikes and igneous bodies cropping out in the northern ,united ,states and ,canada4 ,many of the boulders have been rounded by weathering1 and their shape1 together with their dark color1 has stimulated the local name 8niggerhead0 for them4 ,illustration3 ,basalt in hand specimen4 ,basalt is a strong1 tough1 well-knit rock that will withstand heavy blows from a sledge hammer1 which usually rebounds upon striking4 ,except for use as rubble stones1 basalt has no commercial value4 ,it weathers characteristically to a yellowish1 brownish1 or reddish surface coating of iron oxide and clay4 ,gabbro and ,diabase ,gabbro and ,diabase are dark-colored1 coarse-grained1 hard igneous rocks1 which may be found in the granite and porphyry regions of southeastern ,missouri and as separate boulders in the glacial deposits north of the ,missouri ,river4 ,both resemble basalt1 which has been described in detail elsewhere1 except that basalt is fine-grained1 whereas gabbro and diabase are coarse-grained 7separate grains easily distinguished without a magnifying glass74 ,the layman is ordinarily not concerned with the technical differences between gabbro and diabase1 which appear about the same4 ,both contain plagioclase feldspar 7see ,,feldspar7 and a dark green mineral of the pyroxene family4 ,illustration3 ,diabase hand specimen4 ,from near ,roselle4 ,gabbro and ,diabase are sometimes called 8black granite40 ,their chief use is as bulk or rubble-stone1 although special varieties may be used for building purposes4 ,coal ,coal is so well known that little need be written about its distinguishing characteristics4 ,most of the coal in ,missouri is of about bituminous rank1 although some cannel coal1 which is discussed below1 is also present4 ,missouri bituminous coal occurs in the northern and western parts of the state4 ,it contains bands of dull coal1 bands of glistening 8glance0 coal1 the sooty 8mineral charcoal10 and common mineral impurities like calcite1 gypsum1 pyrite and marcasite 78sulphur071 clay minerals1 and quartz4 ,bituminous coal breaks with essentially a cubical fracture4 ,it occurs in horizontal or nearly horizontal beds or 8seams10 which may be followed considerable distances laterally without necessarily encountering much change4 ,usually1 a fire clay or a fire clay-like under-clay immediately underlies the coal1 but the overlying rock 7the roof7 may be shale 7slate8 see discussion of ,,shale71 sandstone1 or less commonly1 limestone4 ,illustration3 ,bed of coal exposed by stream erosion1 near ,columbia4 ,coal originates from pre-existing plants and may be thought of as ,mother ,nature's storage cellar of 8preserved0 plant life4 ,the ,missouri coal began millions of years ago as mosses1 tree-like ferns1 conifers1 and various plants that reproduce by spores1 which flourished in great wide-spread swamps4 ,insects were abundant1 as is indicated by their remains4 ,rain was probably plentiful and climate favorable1 so that such vegetation thrived luxuriantly4 ,today1 fallen forest timber of the highland disappears by oxidizing and decaying in the air2 but in swamp land the leaves1 stems1 pollen and woody trunks fall into and under water and under favorable conditions decompose through bacterial and chemical action into layers and pools of slippery1 oozy1 blackish humic gel 7like brownish black gelatin1 8jello071 which remains4 ,likewise1 in ages past1 more and more plant material continued to live1 fall1 and accumulate in the old coal swamps until very thick deposits of the woody gel existed4 ,eventually land-sea or climatic conditions changed1 and plant life died out as mud1 sand1 or other rock-forming material was swept in to cover1 as a lid1 the stored-up plant remains4 ,the weight of overlying beds squeezed out excess water from the woody gel1 and from the time of covering through the present day1 gases 7like mine gases71 and other volatile constituents of the coal have been given off4 ,a bed of coal1 which consists chiefly of black combustible carbon1 with volatile constituents and non-volatile ash substances1 has resulted4 ,man uses the coal by burning it directly1 or it may be coked and the volatile constituents recovered in coal tar and other compounds4 ,the mineral impurities like the calcite1 gypsum1 clay1 sand1 and brassy pyrite or marcasite1 are shaken through the grates as ash or melted as clinkers4 ,in nature1 the pyrite and marcasite minerals may oxidize in ground water percolating over them to form dilute sulphuric acid1 the acid mine waters4 ,cannel coal in ,missouri has been found chiefly in old sinkhole deposits through part of central ,missouri4 ,it is characterized by fracturing conchoidally and having a more massive structure 7instead of the layered structure common to bituminous coal74 ,cannel coal burns to a very hot1 rather quick fire because of high volatile content1 and is thought to have developed from accumulations very rich in plant spores4 ,coal mining is an important industry in ,missouri1 and a special bulletin on coal has been published by the ,state ,geological ,survey at ,rolla1 ,missouri4 ,pyrite and ,marcasite ,pyrite and ,marcasite 7,fool's gold1 8sulphur07 are brassy yellow1 metallic1 heavy minerals which will scratch glass but which cannot themselves be scratched by a knife1 and which will leave a dark-greenish to black mark or streak when rubbed across unglazed porcelain or chert rock4 ,both are composed of iron sulphide1 ,fe,s--iron #df4f per cent1 and sulphur #ec4d per cent4 ,although they have the same chemical composition1 they differ in internal atomic and crystalline structure1 which is of interest to scientific mineralogists4 ,pyrite may crystallize in cubes1 or in forms called pyritohedrons1 named from pyrite1 whereas marcasite crystallizes in characteristic arrow-shaped or cockscomb forms4 ,marcasite weathers a little more readily than does pyrite1 but otherwise they are much the same to the casual observer4 ,pyrite and marcasite have been called 8fool's gold0 because so many persons have been fooled1 sometimes with serious financial consequences1 by their slight resemblance to true gold4 ,true gold is soft1 usually slightly orange-yellow in color1 malleable1 and unaffected by ordinary acids2 and it leaves a gold-colored streak when rubbed on unglazed porcelain or a hard white rock4 ,pyrite1 in contrast1 is quite hard 7harder than steel71 is brassy yellow with perhaps a slight greenish tinge except where tarnished1 is brittle1 is corroded by acids or oxidizing ground waters1 and leaves a greenish black to black streak on a white rock4 ,one readily notices the difference in color between pyrite and gold 7such as is in a piece of good quality jewelry71 when the two are viewed close together4 ,yellowish1 partially weathered mica has also been mistaken for gold4 ,illustration3 ,brassy1 granular pyrite in hand specimen4 ,illustration3 ,pyrite in crystal cubes1 and replacement of fossils4 ,pyrite and marcasite occur abundantly in most of the metal-mining districts of ,missouri1 as the 8brass10 or 8sulphur balls10 etc41 in coal1 as small nodules or pellets in some limestone1 shale and sandstone1 as replacements of fossils1 and as minute crystals in granite1 porphyry1 and the other igneous rocks4 ,several marcasite mines have been developed in old sinkhole deposits in south central ,missouri1 but these are not in production at the time of this writing4 ,the sinkhole iron mines of south central ,missouri contained pyrite-marcasite before oxidation to the iron oxide ore1 and some of them still contain the sulphides in their lower levels4 ,illustration3 ,marcasite crystal cluster from ,joplin region4 ,the arrowhead or cockscomb crystal form is characteristic of marcasite4 ,marcasite weathers 7oxidizes7 very readily under most conditions1 with the formation of 7#a7 yellowish brown iron oxide1 the mineral limonite1 which may stain rocks1 soil1 stream bank1 etc41 and 7#b7 weak sulphuric acid water4 ,the sulphuric acid solution may react with more marcasite or pyrite and evolve a gas1 hydrogen sulphide1 ,h,s1 which has a rotten-egg odor4 ,this explains the foul odor often noticed around old coal mine dumps4 ,heat is evolved in these reactions1 and coal waste on the dump may be ignited by the heat of the chemical reactions4 ,the burning pyrite1 or elemental sulphur1 gives off sulphur dioxide1 8burning sulphur fumes10 which add to the odor and heat around a coal mine dump4 ,the burning coal waste and the chemical reactions may raise the temperature of the coal waste pile high enough to fire or 8burn0 the shale rock to a red1 partially vitrified1 natural brick-like material1 which is sold or distributed as 8coal dump shale0 or 8burned shale10 or 8red shale0 for all-weather surfacing of drives or walks4 ,pyrite and marcasite have been used in the commercial manufacture of sulphuric acid1 but elemental sulphur can now be utilized more economically1 so that now no market exists for pyrite or marcasite in ,missouri4 ,in earlier times only large deposits containing thousands of tons of the mineral had any value4 ,in some foreign countries pyrite is burned and the fumes utilized for the manufacture of sulphuric acid1 while the cinder1 an iron oxide and iron ore1 is smelted to recover metallic iron4 ,the origin of pyrite and marcasite is as variable as its enclosing rock4 ,no general statement can be made which will include the igneous rock pyrite1 the ,joplin marcasite1 the 8sulphur0 of the coal1 and occurrences in sink holes and various sedimentary rocks4 ,a discussion of all these origins alone would fill a pamphlet as large as this one on ,missouri rocks4 ,conglomerate ,conglomerate is a rock composed of gravel1 pebbles1 and boulders cemented together1 with more or less sand and clay between the larger fragments4 ,it is truly a conglomeration of rock fragments as one would find loose today in a stream or ocean shore gravel bar1 or in a hillside gravel bank4 ,probably the conglomerate most abundantly exposed in ,missouri is that overlying the igneous rocks in the southeast part of the state4 ,gneiss ,gneiss is a hard1 granular rock which exhibits a coarsely banded structure 7resulting from metamorphism74 ,the bands are evident because of color differences due to different mineral content2 those dark in color are commonly rich in dark mica 7biotite7 or hornblende 7a dark green to black1 hard mineral71 whereas the light bands contain feldspar and quartz4 ,many gneisses have about the same mineral composition as granite2 hence1 for our nontechnical purposes1 a banded rock1 otherwise granite-like1 is a gneiss4 ,illustration3 ,gneiss typically banded4 ,gneiss is a metamorphic rock1 a changed rock4 ,the banded structure was developed by a combination of very high pressure1 high temperature1 and solutions acting on a previously existing rock in essentially a solid condition4 ,the original rock may have been an igneous or sedimentary rock which has been crushed or made to flow into bands1 or has been re-crystallized4 ,the tremendous pressure which operated during the banding of most gneisses also crumpled square miles of rock thousands of feet thick into folded and broken 7faulted7 mountains4 ,true slates1 marbles1 and some quartzites are formed from soft shales1 limestones1 and sandstones1 respectively1 in the metamorphic process4 ,almost no metamorphic rock of this regional type crops out in ,missouri1 but the boulders of gneiss which are found in the glacial deposits were picked up in ,canada or the northern ,united ,states and carried to ,missouri by a continental glacier thousands of years ago4 ,except for use as bulk stone or possible structural purposes the gneiss in ,missouri has no value4 ,the glistening yellowish mica sometimes seen in gneiss is not gold1 of course1 and is likewise valueless4 ,hematite ,hematite 78keel07 is a heavy1 red to purplish red1 dull to glistening mineral which leaves a red mark or streak when rubbed on a hard white rock 7like chert7 or on unglazed porcelain4 ,this red color of hematite coating or stain is responsible for our red clays1 red soils1 red iron rust1 reddish creek-water1 and almost every bit of natural1 red mineral matter in ,missouri4 ,hematite is iron oxide1 ,fe,o1 and has a close associate1 limonite1 which is yellow to brown in color1 and has the chemical composition ,fe,on,h,o4 ,the two are mentioned together here because they are commonly associated in nature1 where they can be recognized in mixture by the yellowish red or reddish brown colors on rocks or soils4 ,individual discussion is given limonite under its heading1 but its relationship to hematite is repeated here for obvious reasons4 ,illustration3 ,hematite3 glistening1 fine-grained1 and dark red4 ,illustration3 ,hematite makes a deep red mark or streak on a hard white rock or unglazed porcelain4 ,hematite varies in hardness enough that some specimens can be scratched easily with iron1 whereas others are almost as hard as that metal itself4 ,where clay occurs mixed with hematite1 as in paint ore1 it may be quite soft1 but 8blue kidney ore0 is usually hard4 ,hematite is the ore 7iron ore7 mineral at ,iron ,mountain and ,pilot ,knob mining districts and in the various sink-hole mines or pits in south central ,missouri4 ,scattered boulders of hematite occur in non-commercial quantities within a shaly layer 7lower part of ,pennsylvanian age rocks7 which crops out extensively in central ,missouri1 and the finding of these boulders has at times1 unfortunately1 stimulated short-lived hopes of locating a valuable deposit of iron ore4 ,flaming red soil or mountains of red solid rock 7as are present in western ,united ,states7 may be colored by less than five per cent iron oxide and are in no sense iron ore because the iron is not concentrated4 ,iron is the fourth most abundant element in the earth's crust1 but workable iron mines and deposits are few and far between4 ,to be commercially valuable an iron ore deposit must contain tens of thousands of tons and be relatively free from impurities1 notably sulphur and phosphorus4 ,hence1 not many ,missouri farms are locations of iron ore deposits4 ,the origin of ,missouri hematite is about as diverse as its occurrences4 ,hot iron-rich solutions coming from an igneous source below are believed to have introduced the hematite in the ,iron ,mountain-,pilot ,knob area1 but the sink-hole hematite resulted from the oxidation of iron sulphide4 ,weathering of older iron-containing rocks and minerals gave rise to the coloring hematite seen on our sub-soil and surface rock4 ,hematite is used as a polishing agent1 as a pigment in paint1 and1 of course1 as an ore of metallic iron4 ,in the smelting of iron from hematite the ore is mixed in a huge1 chimney-shaped blast furnace with coke 7from coal7 and limestone4 ,air is blown into the furnace as into a blacksmith's forge2 and the coke and gasses1 burning at an incandescent heat1 take the oxygen from the ,fe,o1 leaving metallic iron which melts and is run out of the furnace at periodic intervals4 ,thus the smelting process is the opposite of the rusting process4 ,the impurities and cinder run out as molten slag4 ,limonite ,illustration3 ,dark brown limonite4 ,illustration3 ,stalactitic limonite from southeastern ,missouri4 ,limonite is a heavy1 yellow to brown1 or brownish black mineral which always leaves a yellow to brown mark or streak when rubbed across a hard white rock or unglazed porcelain4 ,it usually has a dull luster on a broken surface1 and may vary from thumb-nail hardness to almost that of steel4 ,the distinguishing test is its yellow to brown streak4 ,in composition limonite is iron oxide which contains more or less water chemically combined1 ,fe,on,h,o4 ,that is1 it may be dried bone-dry at the temperature of boiling water1 but upon heating to redness the additional1 chemically held water will be driven off4 ,limonite is ordinarily formed from the weathering of other iron-containing minerals 7pyrite1 for example7 and is therefore a wide-spread mineral in surface rock1 in films on pools of water1 and in soil1 all of which it colors yellow to brown4 ,in fact1 almost all of the yellow to brown inorganic mineral color and stain seen in nature is that of limonite4 ,commercial deposits of limonite occur in southeastern ,missouri where large boulders1 discontinuous and irregular lenses or beds1 pipes1 nodules1 and gravel to clay-sized particles of the mineral are associated with the cherty1 gravelly residual clay4 ,usually the ore is crushed1 hand-sorted1 and washed preparatory to concentration for shipment to a furnace or for use in cement manufacture4 ,as in the case of hematite1 unless one has a deposit amounting to thousands of tons of ore it has little commercial value1 and unless the mineral is relatively pure it can not be used4 ,paint ,ore or ,red ,ochre ,an intensely red-colored1 clayey iron ore has been mined for paint pigment in several deposits in south central ,missouri4 ,it occurs in sink hole deposits like those containing fire clay4 ,brown ocher may be available from southeast ,missouri4 ,iron ,band ,diaspore ,shells of red or reddish brown iron oxide occur about cores of diaspore clay in some of those deposits south of the ,missouri ,river4 ,previously this material had no value1 but in the last few years it has been purchased for and shipped to a cement company1 which used it in the manufacture of cement4 ,diaspore clay is discussed elsewhere in this pamphlet4 ,manganese ,ore ,several manganese minerals make up the manganese ore which occurs to a limited extent in southeast ,missouri1 principally in ,shannon1 ,reynolds1 ,carter1 ,iron1 and ,madison counties4 ,although the ,missouri manganese minerals are usually heavy1 black or nearly so1 and have a black or brownish-black mark or streak1 the identification of the individual minerals is difficult and should be left to a technically trained mineralogist4 ,manganese minerals are used in the chemical industry and in the production of certain kinds of iron4 ,a special report on the manganese deposits of ,missouri is available at the ,missouri ,geological ,survey1 ,rolla1 ,missouri4 ,galena ,galena 78lead07 is a heavy1 soft1 somewhat brittle ore of lead4 ,it has a brilliant metallic luster1 and silvery gray color on a freshly broken surface4 ,where weathered it appears dull gray4 ,it can be scratched with a knife1 and breaks with surfaces at #ij1 forming cubes4 ,the unbroken1 original crystal form of galena which has grown unobstructed in a vein opening is commonly cubical in habit or a modification thereof4 ,it leaves a dark1 lead-gray to black mark or streak when rubbed across unglazed porcelain or chert4 ,illustration3 ,a 8cube0 of galena4 ,illustration3 ,cluster of galena crystals from ,joplin region4 ,galena is lead sulphide1 ,pb,s1 and when pure contains #hf4f per cent lead and #ac4d per cent sulphur4 ,small amounts of silver may also be present4 ,galena commonly occurs in ,missouri as a cavity filling in crushed limestone or chert1 or as a replacement in limestone or dolomite1 or in shale1 so that a large quantity of practically worthless enclosing rock 7gangue7 must be taken out in order to obtain the desired galena4 ,if a person desires to estimate the value of his galena 7lead7 prospect by having an analysis or assay made of his ore1 he must include in his sample the gangue rock that would of necessity have to be taken out when mining his ore4 ,too often persons carefully select for analysis a choice galena specimen which may run over #hj lead1 only to find that as a practical mine product it would be reduced to less than #e lead in all the rock which also would have to be taken out4 ,after a galena ore is mined it is customarily crushed and the galena removed from the gangue by a gravity-separation process which takes advantage of the difference in 8heaviness0 7specific gravity7 between galena 7#g4e7 and limestone 7calcite7 or chert 7#b4g-b4f71 or by a froth flotation process in which the galena is preferentially wetted and carried off by an oily froth or foam4 ,the galena concentrate is roasted to burn out the sulphur1 reduced by carbon1 and smelted to metallic lead4 ,the origin of some ,missouri lead deposits is debatable1 but the writer believes the most reasonable explanation to be that warm1 chemically active waters arose from an igneous body below and carried to the place of deposition the lead which they held in solution4 ,missouri is one of the leading producers of lead in the world from its ,flat ,river1 ,fredericktown1 ,joplin1 and central ,missouri districts1 from which in #aida lead concentrates having a value of over #ae1jjj1jjj were produced4 ,sphalerite ,sphalerite 7locally called ,jack1 ,rosin ,jack1 ,black ,jack1 ,ruby ,jack1 ,zinc1 ,rosin ,spar7 is a tan-brown1 resinous1 brown or brownish black mineral having a very high luster on its broken 7cleavage7 surfaces4 ,much of it so strongly resembles lump rosin that the term 8,rosin ,jack0 is truly descriptive4 ,less commonly1 a ruby red variety occurs as crystals perched on other sphalerite or on waste rock4 ,sphalerite is readily scratched with steel4 ,its chemical composition is zinc sulphide1 ,zn,s--zinc #fg per cent1 sulphur #cc per cent--and it is an important ore of zinc4 ,sphalerite occurs abundantly in the mining district of southwest ,missouri1 but small1 non-commercial amounts of it have been found through an area extending even north of the ,missouri ,river4 ,at the mines1 after the ore and rock are taken out1 they are crushed and separated1 the ore going to the smelter and the rock to tailings piles4 ,under the old milling process employed in southwestern ,missouri1 thousands of tons of coarse tailings1 largely chert1 were poured onto huge 8chat0 piles1 many of which remain as a low-priced by-product for some one to put to use4 ,this chat differs mineralogically from the southeastern ,missouri chat1 which is largely dolomite4 ,illustration3 ,sphalerite from near ,joplin4 ,barite 78,tiff07 ,barite 78,tiff0 in southeast ,missouri1 ,heavy ,spar1 ,barytes7 occurs in ,missouri predominantly as a white1 quite heavy1 soft1 non-metallic mineral which has a high luster on a freshly broken surface4 ,slightly bluish 8glass0 barite or 8glass tiff0 has been found in smaller quantity with the more abundant1 opaque white material4 ,the glassy barite may superficially resemble calcite or selenite gypsum1 but in distinction1 barite breaks or cleaves to surfaces joining at right angles and does not effervesce with acid1 whereas calcite does effervesce in acid and cleaves at oblique angles 7rhombohedral cleavage74 ,gypsum is so soft that it can be scratched very easily with the thumb-nail1 whereas barite is scratched with difficulty1 if at all1 by the thumb-nail4 ,notably1 again1 barite is 8heavy10 with a specific gravity of about #d4e1 whereas calcite1 gypsum1 limestone1 and chert are 8lighter10 with a specific gravity of about #b4f to #b4g4 ,barite has the composition barium sulphate1 ,ba,s,o1 of which barium oxide constitutes #fe4g per cent4 ,illustration3 ,three pieces of barite1 the crested and bladed form at the left1 8glass0 barite in the center1 and a small crystal at the right4 ,barite occurs in abundance in the ,jefferson-,washington counties district1 which furnishes about #hj of ,missouri production4 ,other production comes from near ,houston1 ,texas county1 and from the central district--,miller1 ,moniteau1 ,morgan1 ,cole counties1 and adjacent territory4 ,in the ,jefferson-,washington counties district1 it is dug from residual clay over dolomite and is run through washing and concentrating mills which remove the clay and lighter waste rock4 ,most of the central district production comes from old sinkhole deposits1 the ore being also crushed1 washed1 and concentrated in preparation for shipment4 ,missouri barite which was produced during #aida had a value of over #a1cjj1jjj and constituted about #dj of the total ,united ,states productions4 ,barite is used as a paint pigment and extender1 as a flux1 as a source of barium in the chemical industry1 as a filler in rubber1 paper1 oil cloth1 textiles1 and leather1 and as a heavy substance in oil well drilling mud4 ,the largest single use is in the manufacture of lithopone paint4 ,gypsum ,gypsum is a soft mineral which can be scratched easily with the finger or thumb-nail4 ,it may be glassy or transparent1 or may grade into an opaque white body1 possibly stained by iron oxide1 but it is always very soft4 ,of the three varieties of gypsum--selenite1 alabaster1 and satinspar--only the first two have been found in ,missouri by the writer4 ,the chemical composition of gypsum is ,ca,s,o#b;,h,o4 ,illustration3 ,transparent1 flexible variety of gypsum 7selenite74 ,illustration3 ,fine-grained1 white1 opaque gypsum 7alabaster74 ,the chief use of gypsum is in the manufacture of plaster of paris1 during which it is pulverized and heated to drive off part of the water of crystallization so that its composition corresponds to ,ca,s,o,h,o4 ,this powder1 when mixed with water and poured into a mold1 heats and sets2 that is1 it hardens by taking up enough of the water to restore its original composition4 ,although thick1 wide-spread beds of gypsum occur in other localities1 probably most of the gypsum in ,missouri has been secondarily formed1 as from the reaction of sulphuric acid from oxidizing pyrite on calcite2 and its quantity is limited to small crystals1 veins1 and crusts in or on other rocks4 ,gypsum may be an impurity in coal1 and some beautiful crystals a few inches long have been found in weathering clay deposits4 ,it therefore cannot be considered as a commercially valuable mineral of this state4 ,meteorites ,meteorites1 the rock-like specimens which have come to our earth as sparkling meteors in the sky1 are perhaps the most prized specimens which the average collector hopes to find1 and perhaps more specimens are mistaken for meteorites than for any other geological substance4 ,meteorites are rare and not easy to find2 they are also not easy to determine4 ,the iron variety is usually a heavy1 roughly-pitted1 brown1 tough1 metallic1 nickel alloy of iron4 ,therefore1 a positive chemical test for nickel is usually strongly suggestive of a meteoric origin1 but confirmation almost requires that a surface be polished and etched with dilute acids to bring out typical and characteristic structures4 ,illustration3 ,the polished and acid-etched surface of an iron meteorite4 ,shows the ,widmanstatten figures characteristic of iron meteorites4 7,photo courtesy of ,american ,museum of ,natural ,history1 ,new ,york74 ,the stony variety of meteorites usually contains a rock-forming mineral called olivine1 beneath its pitted brown surface4 ,in case of either variety1 since special equipment is required for final testing and determination1 it is recommended that this be done at a laboratory appropriately equipped4 ,gold ,gold is not known to occur in ,missouri1 except for very small quantities which have been carried into the state with the glacial deposits in the north half4 ,miners have searched carefully1 and geologists have studied ,missouri rocks intently1 comparing them with the gold veins of the western states1 but they find no promise of a gold deposit in ,missouri4 ,we have been favored with other geological products1 but it is a waste of time to search for gold in ,missouri4 ,silver ,silver has been recovered from ore in the ,silver ,mines area in ,madison county and from the galena of southeastern ,missouri4 ,except for occurrences within the igneous rock area and the lead mining regions1 geologists do not expect to find additional silver ore deposits4 ,diamonds ,no diamond has ever been found in native ,missouri rock4 ,it is possible for diamonds to have been carried into the state with the glacial deposits in the northern part1 but the probability of finding one1 if it did come in1 is extremely remote4 ,diamonds do occur in one part of ,arkansas1 but those rocks are strikingly different from all ,missouri rocks except in a few localities1 having small areas about the size of one's house1 in the southeastern part of the state4 ,the writer has received quartz and calcite crystals for testing from persons who hoped they might be diamonds4 ,it is almost a foregone conclusion that diamonds do not occur in ,missouri4 ,a diamond may be recognized by its extreme hardness4 ,it is the hardest substance known1 natural or artificial1 and will scratch any known substance2 but it1 in turn1 is scratched only by another diamond4 ,acids do not affect diamonds in the least4 ,uranium ,minerals ,three uranium-containing minerals1 tyuyamunite 7pronounced tyew-yuh-moon-ite71 possibly carnotite1 and metatorbernite1 have been found in ,missouri but none has been mined commercially4 ,tyuyamunite and carnotite are canary yellow powdery minerals so similar in appearance they can be differentiated only by chemical and x-ray properties4 ,both minerals contain uranium1 vanadium1 oxygen1 water1 and one other element1 which1 if it is calcium1 the mineral is tyuyamunite1 but if it is potassium the mineral is carnotite4 ,the canary yellow color referred to is distinctly different from the brownish or reddish yellow color of iron oxide minerals4 ,these yellow uranium minerals have been found near ,ste4 ,genevieve along cracks in limestone and in the black shale above the limestone1 and in dark1 sandy shales near ,shelbina1 and elsewhere north of the ,missouri ,river4 ,black shales 7high in organic matter7 of marine origin are the most highly radioactive1 whereas black shales deposited on land 7as with coal71 and all shales of other colors are usually lower in radioactivity4 ,metatorbernite is a soft1 pale apple-green scaly mineral that has been found in paper-thin cracks in flint fire clay deposits4 ,it contains uranium1 copper1 phosphorus1 oxygen1 and water4 ,all of these uranium minerals activate a ,geiger counter4 ,,miscellaneous ,,rock ,,structures ,concretions ,a concretion is an aggregate of inorganic matter in the shape1 roughly1 of a ball1 disc1 rod1 or irregular nodular body4 ,usually the aggregation or accumulation started around a small center grain or particle and continued in the growth of layers about it like the shells of an onion1 or in the growth of needle-like fibers which radiate from the center like pins stuck into a spherical pin cushion4 ,concretions vary in size from buck-shot 7buck-shot concretions in the soil7 to oddities ten or twenty feet in diameter1 or even longer in elongate forms4 ,the variety about one-sixteenth or one-thirty-second of an inch in diameter is called an oolite 7pronounced oh-oh-lite74 ,some chert of southern ,missouri1 most of the diaspore and burley clay1 and a limestone cropping out near ,louisiana1 ,missouri1 are made up partly to almost entirely of oolites4 ,see page #bi4 ,concretions may be composed of pyrite1 calcite1 limonite1 chert1 cemented sandstone1 or even cemented clay4 ,they are usually recognized by their structure after the previously enclosing rock has been eroded4 ,thus pyrite1 limonite1 or calcite 7limestone7 concretions remain after shale has softened and washed away1 chert remains after limestone1 and strongly cemented 8irony0 7limonite or hematite7 or siliceous sandstone concretions may be found on the outcrop where the softer or less resistant host rock has been carried off4 ,the irregular-shaped1 intergrown1 nodular limestone concretions 7sometimes called 8loess-kinder01 or loess dolls7 in the upper part of loess deposits along the ,missouri and ,mississippi ,rivers can be found remaining on rain-washed slopes4 ,limy1 mudstone concretions and brown iron carbonate concretions are abundant in certain localities in northwestern and southeastern ,missouri1 where they are used as oddities in rock gardens or walls4 ,illustration3 ,concretions4 ,dark1 limy concretion at left and brassy pyrite at center and right4 ,note the inter-grown pair in center4 ,some concretions are formed at the same general time as the surrounding rock accumulates1 but others may be formed years after the surrounding rock has been buried or removed from the environment of its formation4 ,in either case1 deposition of the mineral matter follows the pattern of addition or 8growth0 from inside out4 ,this growth1 of course1 does not involve a life process like that of a plant or animal4 ,if two or more centers of deposition occur close together1 the several growing concretions may touch1 intergrow1 and develop some weird forms1 suggesting organic growth4 ,however odd these curiosities may become1 there is no question that they are not fossils1 or evidence of life4 ,probably concretions excite the interest of persons more than any other rock structure4 ,ground water1 carrying calcium carbonate1 silica1 or iron compounds in solution1 is a great concretion builder4 ,it percolates through sandstone or other permeable rock and slowly leaves behind enveloping layers or additions of mineral matter1 until a concretion is formed1 to remain hidden from view until its host rock is softened and removed by the action of the weather4 ,geodes ,a geode is usually a hollow1 more or less spherical or ball-shaped shell of mineral and crystal growth which has formed within surrounding rock4 ,missouri geodes commonly vary in size from hickory nuts to small watermelons1 although neither direction of variation is limited4 ,they weather out abundantly at several localities in northeast ,missouri from the so-called ,warsaw formation1 a limy shale4 ,here they are dark brown1 rough and irregular on the outside1 but where broken open show many brilliant1 glistening faces of intergrown quartz crystals4 ,less frequently calcite1 chalcedony1 kaolinite1 and rarely millerite 7nickel sulphide7 may occur in ,missouri geodes4 ,illustration3 ,typical small geode from northeastern ,missouri4 ,the minerals and crystals of a geode grow inward from the walls of a cavity in the rocks4 ,the mineral matter is carried there in solution by ground water and crystallizes out very much more slowly but in the same manner that sugar or salt crystals develop in a saturated solution of those substances4 ,if crystal growth continues until the geode is solid1 it may bear superficial resemblance to a concretion1 but the latter structure is one which has grown outward4 ,the idea of 8growth0 in either case is that of mineral crystallization and enlargement1 but does not in the least involve life like that of a plant or animal4 ,geodes have no value or use other than for ornamental purposes4 ,fossils ,fossils are also found and collected by persons who are interested in rocks and minerals4 ,the varied remains of plants and animals long since petrified or replaced by mineral matter have stimulated the curiosity and become a source of enjoyment to many persons1 from those who merely give a passing glance to the peculiar organic structures in the rocks to those who make a serious hobby or business of collecting and classifying the unreplaceable heritage from the ancient rocks4 ,fossils are interesting in part because of their variety1 for they include petrified wood1 shells like those of oysters1 fish teeth1 foot-prints1 amber1 dinosaur eggs1 coal1 imprints of fern leaves1 of insects1 and of fishes1 and the bones of small and gigantic dinosaurs and elephants4 ,in fact1 a fossil is any evidence of life in the geologic past preserved in the rocks4 ,missouri rocks furnish fossils ranging in size from microscopically small fish teeth to the big skeletal remains of the mastodon1 an ancestor of the elephant2 but the most common ones are the structures and shells of ancient clams1 corals1 brachiopods1 crinoids1 and trilobites4 ,illustration3 ,a tooth of a mastodon1 about one-half natural size4 7,photo courtesy of ,mr4 ,j4 ,r4 ,morrison1 ,louisiana1 ,missouri47 ,illustration3 ,fossils4 ,upper row1 coral on left1 trilobite on right2 center row1 brachiopods2 lower row1 coiled cephalapod1 crinoid head1 and a bryozoan spiral4 ,the accompanying photographs illustrate a few fossils that may be found within our state1 but a thorough1 non-technical treatment of ,missouri fossils is available in a companion volume to this booklet1 8,the ,common ,fossils of ,missouri0 by ,prof4 ,a4 ,g4 ,unklesbay1 ,missouri ,handbook ,no4 #d4 ,the study of fossils1 or paleontology1 is a fascinating branch of geology which extends far beyond the recognition and cataloging of the specimens4 ,it has been found that certain particular fossils occur in rocks of the ages which produce petroleum1 and the search for that valuable substance has been directed in many instances by the fossil content of the rocks4 ,rocks of different ages carry different fossil assemblages1 and a man skilled in paleontology utilizes the fossils in dating geologic history like the page numbers in a book of human history4 ,further1 any student of present-day animals and plants is aided in his understanding of them if he knows the fossil record of their ancestors of the long geologic past4 ,arrow ,heads and ,other ,indian ,artifacts ,arrow heads1 scrapers1 rock knives and saws which were left by the ,indians who formerly lived in ,missouri may be found in moderate abundance in many parts of the state4 ,usually these artifacts are chert in its various colors1 white1 gray1 mottled1 reddish1 or black 7flint74 ,see the discussion of chert on page #cd4 ,chert1 because of its conchoidal fracture1 lack of cleavage1 resistance to chemical weathering1 and superior hardness1 is an exceptionally useful rock for making tools and weapons4 ,hammers and axes of basalt1 and arrow heads of rhyolite are less abundant than the chert artifacts4 ,,the ,,rocks ,,of ,,missouri ,geologists classify rocks into these groups3 igneous1 sedimentary or metamorphic4 ,representatives of all three have been described in the preceding pages4 ,illustration3 ,arrowheads made from white1 gray1 pink1 and black chert4 7,courtesy of ,mr4 ,a4 ,a4 ,jeffrey1 ,columbia1 ,mo47 ,sedimentary rocks are those whose particles settled down through the air or water to form rocks in layers or beds2 hence layered1 bedded1 or so-called stratified rocks are sedimentary rocks4 ,for instance1 the sand and mud settling out of the ,gulf of ,mexico 7or ocean7 after being brought in by the ,mississippi ,river is on its way toward becoming sandstone and shale4 ,limestone is forming off the coast of ,florida now4 ,all of these rocks are accumulating in layers4 ,where one sees regularly-layered or stratified rocks in streams1 road cuts1 quarries1 bluffs or hillsides1 he expects them to be sedimentary rocks4 ,the sedimentary rocks that have been described herein include3 ,limestone ,dolomite ,chert ,shale ,fire clay ,flint fire clay ,diaspore and ,burley clay ,sandstone ,quartzite ,travertine ,coal ,igneous rocks are those which solidified from a hot liquid which was either forced into older surrounding rocks 7intrusive7 or discharged on the earth's surface as a lava flow or products from a volcano 7extrusive74 ,the examples given below illustrate the two types4 ,everyone knows about the extrusive forms from accounts of present-day volcanoes and occasional lava flows1 like those of ,vesuvius1 ,paricutin1 and ,mauna ,loa4 ,an intrusion was injected beneath the ,yellowstone ,park area years ago1 and its heat1 with steam and gases1 is contributing to the unusual natural features which are found in the park and which make it famous4 ,igneous rocks in ,missouri are3 ,granite ,porphyry1 ,rhyolite1 ,rhyolite porphyry ,gabbro and ,diabase ,basalt ,metamorphic rocks are rocks which have been changed through the effects of tremendous pressure 7enough to raise mountains7 and high temperature while in the solid state4 ,in most cases a banded rock results4 ,the metamorphic rocks mentioned in this booklet are3 ,gneiss ,marble ,no doubt it has become apparent to the reader that rocks ordinarily occur in great quantities1 that they are composed of multitudes of grains 7mineral grains71 and that their properties and compositions vary with the different minerals which are present in the grains of the rock4 ,a rock can1 therefore1 be different from a mineral4 ,in fact1 a rock may be defined as 8an aggregate of mineral particles10 or more broadly 8a typical part of the earth40 ,to focus closer attention on minerals we may discuss them for their own sake below4 ,,minerals ,,of ,,missouri ,a mineral is characterized by a constancy of composition and of properties which sets it apart from rocks which vary widely4 ,minerals may be metallic1 like pyrite1 or non-metallic1 like barite2 they may be ore1 like galena1 or rock-forming1 like quartz or feldspar2 they may show crystal faces1 or they may be fragments with rounded or broken surfaces4 ,a favored definition teaches that 8a mineral is a naturally occurring1 inorganic substance having a definite chemical composition and definite physical properties1 within limits40 ,the ,missouri minerals listed herein include3 ,quartz ,mica ,calcite ,dolomite ,sphalerite ,galena ,barite ,marcasite ,carnotite ,tyuyamunite ,pyrite ,hematite ,limonite ,gypsum ,pyroxene ,orthoclase feldspar ,microcline feldspar ,plagioclase feldspar ,metatorbernite ,,geologic ,,values ,although the emphasis in this pamphlet has been on the recognition of ,missouri rocks and minerals1 it is not out of order to consider the broad values that they contribute to our civilization4 ,their use as building materials has been noted1 but it should be further recognized that as our timber is being rapidly depleted more and more structures will be built out of earth materials4 ,missouri possesses a wealth of beautiful limestone that is serviceable and readily quarried4 ,where limestone is not near1 there is usually shale or glacial clay which can be used in the manufacture of brick and tile4 ,permanency will be the keynote of the rock and ceramic structures4 ,gravel and sand are abundant in ,missouri for concrete and other varied uses4 ,the soil is ,missouri's most valuable earth material4 ,hundreds to thousands of years of normal weathering are required to develop the rocks and minerals and texture of the inorganic fraction of the soil4 ,we should preserve it and prevent disastrous soil erosion4 ,aside from these more tangible values1 a fascinating and instructive hobby can be made of collecting1 arranging1 and studying rocks and minerals4 ,one gains a fuller understanding and appreciation of nature from their study4 ,the orderliness1 constancy1 and interrelation within the rock and mineral 8world0 is a restful contrast to the one which man often keeps in turmoil4 ,the beauty of a glistening crystal or a polished mineral or stone is as inspiring as a lovely flower1 yet it lasts and lasts through centuries1 a veritable 8rock of ages40 ,suggested ,collateral ,reading ,material ,books on ,rocks and ,minerals ,how to ,know the ,minerals and ,rocks1 by ,pearl2 publisher1 ,mc,graw-,hill ,book ,co41 ,new ,york4 ,a ,field ,guide to ,rocks and ,minerals1 by ,pough2 publisher1 ,houghton1 ,mifflin ,co41 ,boston4 ,gemstones and ,minerals3 ,how and ,where ,to ,find ,them1 by ,sinkankas2 publisher1 ,van ,nostrand1 ,princeton1 ,new ,jersey4 ,look for paper back editions of these and other books which may be widely available4 ,fossils ,the ,common ,fossils of ,missouri1 by ,a4 ,g4 ,unklesbay1 ,missouri ,handbook ,no4 #d4 ,magazines on ,rocks1 ,minerals1 and ,fossils ,rocks and ,minerals1 ,box1 #bi1 ,peekskill1 ,n4,y4 ,gems and ,minerals1 ,p4,o4 ,box #fhg1 ,mentone1 ,calif4 ,the ,mineralogist1 ,p4,o4 ,box #hjh1 ,mentone1 ,calif4 ,american ,mineralogist1 technical official publication of the ,american ,mineralogical ,society1 ,ann ,arbor1 ,michigan1 editorial office1 ,dept4 of ,mineralogy1 ,university of ,michigan4 ,books on ,mineralogy and ,rocks 7,technical7 ,dana's ,manual of ,mineralogy1 by ,hurlbut2 publisher1 ,john ,wiley ,sons1 ,new ,york4 ,dana's ,textbook of ,mineralogy1 by ,ford2 publisher1 ,john ,wiley ,sons1 ,new ,york4 ,mineralogy1 by ,berry and ,mason2 publisher1 ,freeman ,co41 ,san ,francisco4 ,rocks and ,rock ,minerals1 by ,knopf2 publisher ,john ,wiley ,sons1 ,new ,york4 ,guide to the ,study of ,rocks1 by ,spock2 publisher1 ,harper ,co41 ,new ,york4 ,books on ,general ,geology ,introduction to ,geology1 by ,branson1 ,tarr1 and ,keller2 publisher1 ,mc,graw-,hill ,book ,co41 ,new ,york ,city4 ,introduction to ,college ,geology1 by ,holmes2 publisher1 ,macmillan1 ,new ,york4 ,books on ,physical ,geology ,geology1 by ,emmons1 ,thiel1 ,stauffer and ,allison2 publisher ,mc,graw-,hill ,book ,co41 ,new ,york4 ,principles of ,geology1 by ,gilluly1 ,woodford1 and ,waters2 publisher1 ,freeman ,co41 ,san ,francisco4 ,physical ,geology1 by ,leet and ,judson2 publisher1 ,prentice-,hall ,co41 ,new ,york4 ,books on ,historical ,geology ,the ,geological ,evolution of ,north ,america1 by ,clark and ,stearn2 publisher1 ,ronald ,press ,co41 ,new ,york4 ,time1 ,life1 and ,man1 by ,stirton2 publisher1 ,john ,wiley ,sons1 ,new ,york4 ,these books may be borrowed from public libraries1 or purchased from the publishers and retail book stores4 ,at ,columbia1 the ,university ,book ,store1 and the ,missouri ,store ,co41 sell most of them from shelf stock4 ,missouri ,geology ,publications ,missouri has an excellent ,state ,geological ,survey which has published numerous volumes on various geologic topics and areas within the ,state4 ,inquiry about these bulletins1 circulars1 maps1 and individually handled correspondence1 should be addressed to the3 ,state ,geologist ,missouri ,geological ,survey ,rolla1 ,mo4 ,,footnotes #a,this service is also offered by the ,department of ,geology1 ,missouri ,school of ,mines and ,metallurgy1 ,rolla1 ,missouri1 and by the ,state ,geologist1 ,rolla1 ,missouri4 ,,index ,a ,acid1 testing1 muriatic1 hydrochloric1 storage battery1 sulphuric #aj ,agate #cg ,alabaster gypsum #fc ,aluminum #bc ,amethyst #db ,aragonite #ag ,arrow heads #cd1 #ga1 #gb ,artifacts #ga1 #gb ,asphaltic sandstone #cb ,audrain ,county #bf ,b ,barite #ai1 #fa1 #gd ,barton ,county #cb ,basalt #ac1 #dd1 #df1 #dg1 #dh1 #ga1 #gc ,bauxite #bc1 #bi ,biotite mica #dd1 #ed ,black jack zinc ore #fj ,bloodstone #db ,blossom rock #db ,boone ,county #bf ,brick #bb1 #gd ,burley clay #bi1 #ff1 #gc ,burlington limestone #ab ,burned shale #ba1 #ed ,c ,calcite #ab1 #af1 #cg1 #di1 #fa1 #fb1 #fc1 #fe1 #ff1 #fh1 #gd ,calcium carbonate #ab1 #af1 #cg1 #fg ,callaway ,county #bf1 #bg ,cannel ,coal #ea ,carnelian #db ,carnotite #fe ,carter ,county #eh ,carthage marble #ae ,cave deposits #af ,chalcedony #cg1 #fh ,chats #ce1 #dc1 #fj ,chert #ad1 #cd1 #cg1 #db1 #ei1 #fb1 #ff1 #ga1 #gc ,clinton #cc ,coal #bj1 #di1 #ec1 #fc1 #gc ,cole ,county #fb ,conchoidal fracture #bf1 #cd1 #ea ,concretion #ff1 #fh ,conglomerate #ed ,copper #dj1 #ff ,cotton rock #ae ,crawford ,county #bg ,crinoids #ab ,cross-bedding #cj1 #ca ,crystal ,city #cc1 #da ,d ,definition1 rock and mineral #e1 #gc1 #gd ,developing mineral deposit #bd1 #ei ,diabase #dd1 #dh1 #di1 #gc ,diamonds #dj1 #fe ,diaspore clay #bg1 #eh1 #ff1 #gc ,dike #df1 #dg1 #dh ,dolomite #aj1 #aa1 #ah1 #ei1 #fj1 #gc1 #gd ,dolomite chemical composition #ab1 #bj ,double refraction #ah ,drusy quartz #db ,e ,effervescence #aj1 #aa1 #af1 #ag1 #ah1 #ai ,elephant ,rocks #ci1 #da ,f ,feldspar #ch1 #ci1 #dc1 #de1 #df1 #ed1 #gd ,festus #cc ,fire clay #ai1 #bd1 #gc ,flat ,river #fj ,flint #ad1 #cd ,flint fire clay #bf1 #gc ,fool's gold #ad1 #ea ,fossils #ab1 #bb1 #ce1 #cf1 #eb1 #ec1 #fi ,franklin ,county #bg ,fredericktown #fj ,g ,gabbro #ac1 #ch1 #dd1 #dh1 #gc ,galena #ei1 #fe1 #gd ,gasconade ,county #bf1 #bg ,geiger ,counter #ff ,geode #db1 #fg ,geological ,survey1 ,missouri #f ,glacial boulders and deposits #dj1 #dh1 #ee1 #fe1 #gd ,glass 8tiff10 barite #fa ,gneiss #ed1 #gc ,gold #ea1 #ec1 #fe ,granite #af1 #ca1 #ch1 #dc1 #df1 #dg1 #di1 #ec1 #ed1 #gc ,graniteville #ci1 #dc ,gypsum #ai1 #di1 #fa1 #fb1 #fc1 #gd ,h ,hardness #f1 #ai1 #fe ,heavy spar #fa ,hematite #ef1 #ff1 #gd ,hermann #cc ,houston #fb ,hydrochloric acid #aj ,i ,igneous rock #gc ,iron band diaspore #eh ,iron ,county #ci1 #de1 #eh ,iron ,mountain #ef ,iron ore #ef1 #eg ,isinglass #dd ,j ,jack zinc ore #fj ,jasper #ch ,jefferson ,county #fb ,joplin #fj ,joplin dolomite #ai ,k 8,kaoleen0 #cg 8,keel0 #ef ,klondike #cc ,l ,lafayette ,county #cb ,la ,grange #cg ,lava flow #df1 #gc ,lead ore #ei ,lexington #cc ,lime #ac ,limestone #aj1 #bb1 #ec1 #ee1 #ei1 #fb1 #ff1 #gc1 #gd ,limestone1 chemical1 composition #ab1 #bc ,limonite #ec1 #ef1 #eg1 #ff1 #gd ,lincoln ,county #bg ,loess dolls1 -kinder #ff ,m ,madison ,county #ci1 #de1 #eh ,magnesium carbonate #ab ,manganese ore #eh ,marble #ae1 #ee1 #gc ,marcasite #di1 #ea1 #ec1 #eg1 #gd ,maries ,county #bg ,mark of mineral #f1 #ef ,metamorphic rock #ae1 #ba1 #ee1 #gc ,metatorbernite #fe ,meteorites #fd ,mica #ch1 #ci1 #dd1 #ec1 #gd ,microcline feldspar #dd1 #gd ,miller ,county #fb ,millerite #fh ,mineral1 definition #e1 #gd ,missouri ,geological ,survey #f1 #ei ,missouri ,school of ,mines and ,metallurgy #f ,moberly #cc ,moniteau ,county #fb ,morgan ,county #fb ,muriatic acid #aj ,muscovite mica #dd ,n ,nickel #fd 8,niggerheads0 #cb1 #dh ,o ,ochre #eh ,olivine #fe ,onyx #af1 #db ,oolites #bg1 #bi1 #ff ,orthoclase feldspar #dd1 #gd ,osage ,county #bf1 #bg ,ozora marble #ae ,p ,pacific #cc1 #da ,paint ore #eh ,paleontology #ga ,paris #cc ,petrified wood #ce1 #dc1 #fi ,petroleum #ga ,phelps ,county #bf1 #bg ,phenocrysts #df ,pilot ,knob #ef ,plagioclase feldspar #dd1 #di1 #gd ,plaster of paris #fc ,plastic fire clay #bf ,polish on marble and granite #af ,pop-corn flint fire clay #bf ,porphyry #ca1 #dj1 #dd1 #de1 #ec1 #gc ,porphyry1 chemical composition #dj ,potosi #cg ,pyrite #ad1 #di1 #ea1 #eb1 #ec1 #eg1 #eh1 #fc1 #ff1 #gd ,pyroxene #di1 #gd ,q ,quarry #ad ,quartz #cj1 #ch1 #ci1 #dj1 #da1 #de1 #di1 #ed1 #fe1 #fh1 #gd ,quartzite #cb1 #ee1 #gc ,r ,radioactivity #ff ,reynolds ,county #eh ,rhyolite1 rhyolite porphyry #de1 #ga1 #gc ,ripple marks #cc ,rock crystal #db ,rock1 definition #e1 #gc ,rock wool #ac ,rose quartz #db ,rosin jack zinc ore #fj ,rosin spar zinc ore #fj ,ruby jack zinc ore #fj ,s ,sampling rock or ore #ae1 #ei ,sand #ad1 #cj ,sandstone #cj1 #da1 #dc1 #ec1 #ee1 #ff1 #gc ,sandstone1 chemical composition #bc ,satinspar gypsum #fc ,sedimentary rock #gb1 #gc ,selenite gypsum #fc ,shale #ai1 #bj1 #bd1 #ej1 #ec1 #ee1 #ff1 #gc1 #gd ,shale1 chemical composition #bc ,shannon ,county #eh ,silica #ce1 #dc1 #ff ,silver #ei1 #fe ,silver ,mines #fe ,six-sided crystals #af1 #da ,slate #ba1 #ej1 #ee ,soapstone #ba ,soil sweetening #ac1 #ad1 #bj ,sphalerite #fj1 #gd 8,sponge0 limestone rock #ac ,stalactites #af ,stalagmites #af ,state ,geologist1 ,geological ,survey #f1 #bd1 #ea1 #ei ,st4 ,francois ,county #ci1 #de ,st4 ,louis ,county #bf ,st4 ,peter sandstone formation #da ,ste4 ,genevieve #fe ,streak of mineral #f1 #ef ,sulphur #ea ,sulphuric acid #aj1 #ec1 #fc ,t ,texas ,county #fb ,tiff #af1 #fa ,travertine #af1 #gc ,tripoli #cg1 #dc ,tyuyamunite #fe1 #gd ,u ,university of ,missouri ,geology ,department #f ,uranium ,minerals #fe1 #ff ,v ,vanadium #ff ,vernon ,county #cb ,w ,warren ,county #bg ,warrensburg #cc ,washington ,county #fb ,weathered chert #ai1 #ce1 #cf1 #cg ,widmanstatten figure #fd ,z ,zinc ore #fj ,,of ,,related ,,interest ,,the ,,common ,,fossils ,,of ,,missouri ,a4 ,g4 ,unklesbay ,,our ,,storehouse ,,of ,,missouri ,,place ,,names ,robert ,l4 ,ramsay ,,indians ,,and ,,archaeology ,,of ,,missouri1 ,,revised ,,edition ,carl ,h4 ,chapman and ,eleanor ,f4 ,chapman ,,isbn-#ac3 #igh-j-hbfb ,,university ,,of ,,missouri ,,press ,columbia and ,london ,transcriber's ,notes --,silently corrected a few typos4 --,retained publication information from the printed edition3 this e,book is public-domain in the country of publication4 --,in the text versions only1 text in italics is delimited by underscores4