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.