INDUSTRIAL MINERALS AND METALS OF ILLINOIS

J. E. Lamar

The mineral resources of Illinois include many rocks and minerals of varied character and uses. From them are made an array of everyday products whose sources may not even be recognized by the consumer. The user of a glass bottle, for instance, rarely knows that it may have been made from Illinois silica sand, nor is the driver of an automobile generally aware that the Illinois concrete highway on which he is driving probably was constructed from a mixture of cement, sand and gravel, or crushed stone that may have come from Illinois pits or quarries.

The significance of these rocks and minerals to the economy of Illinois is great, although often unappreciated. Of the more than 600 million dollar value of all Illinois mineral production in 1963, almost 200 million was from industrial minerals. The diversity and widespread distribution of these mineral resources lend variety and balance to the mineral industry of the state, and their production, processing, and utilization afford direct and indirect employment to many people.

The term industrial minerals is used as a convenient group term for nonmetallic minerals that are not fuels. In Illinois they include limestone, dolomite, clay, shale, silica sand and other sands, fluorspar, tripoli (amorphous silica), ganister, novaculite, sandstone, feldspar-bearing sands, barite, gypsum, anhydrite, brines, greensand, oil shale, marl, peat, humus, and tufa. The metallic minerals of Illinois are galena (lead ore), sphalerite (zinc ore), pyrite, and marcasite.

This booklet briefly and nontechnically discusses the foregoing materials and some of the work the Illinois State Geological Survey does in gathering information about their occurrence, and character and in developing new uses.

The assistance of many Survey staff members and of many people in the Illinois mineral industry in the preparation of this booklet is acknowledged.