Survey geologists have mapped the chert- and silica-bearing formations
of Alexander and Union Counties and also many of the various kinds of
gravel deposits. Samples have been tested to determine their chemical
composition and the size of the particles composing them. Laboratory
studies by ceramists indicate that novaculite and novaculite gravel,
when suitably processed, can be used for making silica brick, which
withstands great heat. Canister and the gravels of southern Illinois
offer a variety of raw materials awaiting increased industrial use.