Mineral resources include iron, tin, lead, zinc, wolfram, uranium, diatomite, rock crystal. The Kariandusi Prehistoric Site lies next to the Kariandusi Diatomite Plant. Near Chalk Mountain are outcrops of diatomite. It was found during a geology field course in an abandoned diatomite quarry. The industry mines diatomite which is used for various industrial purposes. Other minerals mined in Nevada include construction aggregates, copper, gypsum, diatomite and lithium. They are of Pliocene age, overlying diatomite, pumice, and tuffaceous sandstone layers. These include potential geothermal power, gold, clay, granite, limestone, marble, salt, diatomite, gypsum, pumice, petroleum. Magnesite, fire clay, gypsum, manganese, diatomite, marble, rock salt and perlite are also present. Non-clumping cat litter is often made of zeolite, diatomite and sepiolite. In some places, diatoms were widespread enough to form diatomite deposits. The commercial deposits of diatomite are restricted to Tertiary or Quaternary periods. Among the mineral resources are&colon; ceramic clay, sand, diatomite, dolomite, marble and serpentine. Non-clumping cat litter is often made of zeolite or diatomite. In addition to the rhyolite, tuff and diatomite also comprise the buttes.