W. D. Keller

“ Conglomerate is a rock composed of gravel, pebbles, and boulders cemented together, with more or less sand and clay between the larger fragments. It is truly a conglomeration of rock fragments as one would find loose today in a stream or ocean shore gravel bar, or in a hillside gravel bank. Probably the conglomerate most abundantly exposed in Missouri is that overlying the igneous rocks in the southeast part of the state. ”

“ Weathering of older iron-containing rocks and minerals gave rise to the coloring hematite seen on our sub-soil and surface rock.
Hematite is used as a polishing agent, as a pigment in paint, and, of course, as an ore of metallic iron. In the smelting of iron from hematite the ore is mixed in a huge, chimney-shaped blast furnace with coke (from coal) and limestone. Air is blown into the furnace as into a blacksmith’s forge ”

“ Missouri possesses a wealth of beautiful limestone that is serviceable and readily quarried. Where limestone is not near, there is usually shale or glacial clay which can be used in the manufacture of brick and tile. Permanency will be the keynote of the rock and ceramic structures. Gravel and sand are abundant in Missouri for concrete and other varied uses.
The soil is Missouri’s most valuable earth material. Hundreds to thousands of years of normal weathering are required to develop the rocks and minerals and texture of the inorganic fraction of the soil. ”

“ However odd these curiosities may become, there is no question that they are not fossils, or evidence of life. Probably concretions excite the interest of persons more than any other rock structure.
Ground water, carrying calcium carbonate, silica, or iron compounds in solution, is a great concretion builder. It percolates through sandstone or other permeable rock and slowly leaves behind enveloping layers or additions of mineral matter, until a concretion is formed, to remain hidden from view until its host rock is softened and removed by the action of the weather. ”

“ 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 ocean, where extensive deposits of sand are accumulating, probably destined to become widespread beds of sandstone.
The grains of sand may be broken and become angular during their long trip to the ocean, or they may become rounded by rubbing against each other. If they exist in sand dunes, blown about by the wind before being cemented into rock, the grains usually become somewhat rounded. ”

“ Commercial deposits of limonite occur in southeastern Missouri where large boulders, discontinuous and irregular lenses or beds, pipes, nodules, and gravel to clay-sized particles of the mineral are associated with the cherty, gravelly residual clay. Usually the ore is crushed, hand-sorted, and washed preparatory to concentration for shipment to a furnace or for use in cement manufacture. As in the case of hematite, unless one has a deposit amounting to thousands of tons of ore it has little commercial value, and unless the mineral is relatively pure it can not be used. ”

“ Flaming red soil or mountains of red solid rock (as are present in western United States) may be colored by less than five per cent iron oxide and are in no sense iron ore because the iron is not concentrated. Iron is the fourth most abundant element in the earth’s crust, but workable iron mines and deposits are few and far between. To be commercially valuable an iron ore deposit must contain tens of thousands of tons and be relatively free from impurities, notably sulphur and phosphorus. Hence, not many Missouri farms are locations of iron ore deposits. ”

“ No diamond has ever been found in native Missouri rock. It is possible for diamonds to have been carried into the state with the glacial deposits in the northern part, but the probability of finding one, if it did come in, is extremely remote.
Diamonds do occur in one part of Arkansas, but those rocks are strikingly different from all Missouri rocks except in a few localities, having small areas about the size of one’s house, in the southeastern part of the state. The writer has received quartz and calcite crystals for testing from persons who hoped they might be diamonds. ”

“ The aluminum is there all right, 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 ores. 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 possible, the vast quantities of clay and shale on the earth’s surface must be considered a distant reserve of a prohibitively high cost aluminum. ”

“ For instance, a stone of 90% purity, which is close at hand, will probably be more valuable than one of 98% purity which must be hauled fifteen miles. Bare hillsides or creek banks where a crusher can be set up to handle the stone without extra lifting are preferable for quarry sites. Usually the overburden is less in such an exposed face. Impurities in limestone deposits may be large chert (flint) nodules which can be hand-sorted out, sand grains, clay which settled into and onto the stone during its accumulation, and pyrite (fool’s gold) or other minerals of lesser importance. ”

“ Clay scouts work in secret, mining leases are contested in court, rumors fly fast in English, German, and German-Swiss over the country telephones, prospecting results may be hidden, personal pressure may be brought to influence a deal, and speedy salesmanship is employed when an exciting find is in the offing. When the legends, traditions, and facts of the diaspore region are collected and recorded, an interesting and essential part of Missouri history will have been written. ”

“ Pyrite and marcasite occur abundantly in most of the metal-mining districts of Missouri, as the “brass,” or “sulphur balls,” etc., in coal, as small nodules or pellets in some limestone, shale and sandstone, as replacements of fossils, and as minute crystals in granite, porphyry, and the other igneous rocks. Several marcasite mines have been developed in old sinkhole deposits in south central Missouri, but these are not in production at the time of this writing. ”

“ Granite is a granular (coarse-grained) rock which has a glassy luster and is too hard to be scratched appreciably by steel. It may be white to gray, tan, brown, or pink to red in color, but pinkish to red granite predominates in Missouri. Some black stone, referred to locally as “black granite,” is usually a variety of gabbro. Most Missouri granite is coarse-grained, so that the constituent mineral grains—quartz, feldspar, and (less frequently) mica—can be readily recognized by anyone familiar with those minerals. It makes up many 39 of the mountains and hills in Iron, Madison, and St. ”

“ A pure limestone is composed entirely of calcite. Even impure limestones which contain subordinate amounts of quartz sand, chert, clay, or iron oxide are in the main also calcite. Dolomite and dolomitic limestones contain the mineral dolomite.
The mineral of ordinary marble is calcite; dolomite marble contains dolomite. The cementing material in sandstone and a common accessory mineral in shale are calcite. It is truly a wide-spread and abundant mineral. ”

“ A geode is usually a hollow, more or less spherical or ball-shaped shell of mineral and crystal growth which has formed within surrounding rock. Missouri geodes commonly vary in size from hickory nuts 68 to small watermelons, although neither direction of variation is limited. They weather out abundantly at several localities in northeast Missouri from the so-called Warsaw formation, a limy shale. Here they are dark brown, rough and irregular on the outside, but where broken open show many brilliant, glistening faces of intergrown quartz crystals. ”

“ In fact, it may be mentioned in passing that some basalt and allied dikes have been found cutting through the sedimentary sandstone, shale, and limestone which overlie the igneous granite and porphyry and are much younger.
Missouri porphyry has little use or value other than of bulk or crushed stone.
Basalt
Basalt is a fine-grained, dark-gray, dark-green, or greenish-black rock which is hard enough to be scratched with difficulty by steel. It originated by the solidification of lava. Today, basalt rock is forming where lava at the Hawaiian volcanoes solidifies. ”

“ Ordinary acids do not attack quartz, and it is relatively unaffected by chemical weathering in Missouri. Its composition is silicon dioxide, SiO2.
Quartz occurs in granite as the lustrous, partially rounded grains which constitute perhaps 20% of the rock (feldspar makes up most of the more opaque remainder which breaks with many small flat faces) , and is recognized in the small glistening grains in the porphyry. Hence it is an important igneous rock-forming mineral. ”

“ Man uses the coal by burning it directly, or it may be coked and the volatile constituents recovered in coal tar and other compounds. The mineral impurities like the calcite, gypsum, clay, sand, and brassy pyrite or marcasite, are shaken through the grates as ash or melted as clinkers. ”

“ Missouri has the only locality in the entire world where relatively pure diaspore clay is now mined in commercial quantities. Because of its extreme resistance to fusion under very high temperatures, diaspore has been called the “aristocrat of fire clays.” ”

“ Coal
Coal is so well known that little need be written about its distinguishing characteristics. Most of the coal in Missouri is of about bituminous rank, although some cannel coal, which is discussed below, is also present.
Missouri bituminous coal occurs in the northern and western parts of the state. It contains bands of dull coal, bands of glistening “glance” coal, the sooty “mineral charcoal,” and common mineral impurities like calcite, gypsum, pyrite and marcasite (“sulphur”) , clay minerals, and quartz. Bituminous coal breaks with essentially a cubical fracture. ”

“ Tripoli occurs in the vicinity of Seneca, Newton County, Missouri. It is a light-weight, porous, white to creamy, siliceous rock, which may be scratched because of its softness. Tripoli represents the porous insoluble residue of an earlier rock, which was composed of skeletal insoluble silica and interstitial soluble calcium carbonate (calcite) , the latter having been dissolved away by ground water. Tripoli has a chalky appearance but is totally unlike chalk chemically. Tripoli is nearly pure silica, whereas chalk is calcium carbonate. ”

“ Fossils are interesting in part because of their variety, for they include petrified wood, shells like those of oysters, fish teeth, foot-prints, amber, dinosaur eggs, coal, imprints of fern leaves, of insects, and of fishes, and the bones of small and gigantic dinosaurs and elephants. In fact, a fossil is any evidence of life in the geologic past preserved in the rocks. Missouri rocks furnish fossils ranging in size from microscopically small fish teeth to the big skeletal remains of the mastodon, an ancestor of the elephant ”

“ 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 granite. Because limestone and marble are softer than granite they may be cut and polished at lower cost, but because of their ease of attack by acid, water, and abrasion they soon become dull when used as an exterior stone. ”

“ 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 state.
Dolomite when powdered (by scraping the surface of the specimen, for dolomite is softer than steel or glass) effervesces freely in cold dilute hydrochloric (muriatic) acid, but the lump dolomite effervesces very slowly, if at all. Calcite effervesces freely in the lump with cold dilute acid. ”

“ Hematite (“keel”) is a heavy, red to purplish red, dull to glistening mineral which leaves a red mark or streak when rubbed on a hard white rock (like chert) or on unglazed porcelain. This red color of hematite coating or stain is responsible for our red clays, red soils, red iron rust, reddish creek-water, and almost every bit of natural, red mineral matter in Missouri. ”

“ Because of the high value of diaspore, a highly competitive prospecting, leasing, mining, and brokerage business has developed in the diaspore region. Practically all of the thrills, hopes, disappointments, and good fortunes that are associated with oil booms are found in this business and clay area; clay pits are only smaller in scale than wild oil gushers. ”

“ Diaspore contains a higher percentage of aluminum than does bauxite, the chief ore of aluminum, but because of diaspore’s extremely refractory nature it is less easily reduced to aluminum metal than is bauxite, 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 ore. Where resistance to very high temperature has been required, diaspore super fire brick has been remarkably useful. ”