Although not as visually impressive as glittering silver, gold, or sulfides, nonmetallic resources are just as important to our economy. They are more abundant and less expensive than metallic are deposits.
Stone is removed from quarries as blocks for building purposes or is crushed for highway construction. Most stone is limestone or granite. Limestone is also an important component of cement and is used to replenish lime in farm soil.
Sand and
gravel are mined extensively from shallow open pits for highway construction, cement, and concrete. Well‐sorted sand dune, beach, and glacial outwash deposits are the best sources for sand and gravel. Glass is also produced from
silica sand. Bentonite, a clay mineral, is known for its ability to absorb water and is used in cement and cat litter. Volcanic material such as that in cinder cones can also be a gravel source. Finely ground volcanic pumice is used as an abrasive.
Evaporitic rocks and phosphate deposits, enriched in phosphorous, nitrogen, and potassium, are important sources of agricultural fertilizers. Gypsum, another evaporitic mineral, is important in the manufacture of plaster and wallboard. Rock salt is mined from evaporitic salt beds and salt domes for use as a deicer and a food preservative. Sulfur is recovered from salt domes to make fertilizers, acids, and explosives.
Graphite is widely applied as a lubricant. Asbestos is a unique variety of the mineral serpentine that can be woven into fireproof material (although it is rarely used for this purpose today because it is a carcinogen). Talc is a fine‐grained mineral substance that is used as a lubricating powder. Borates are an important component in cleaning compounds. Barite is a very heavy mineral that is used as a drilling additive in the oil industry. Fluorite is used in toothpaste, Teflon, and the steel industry.
In addition to their value as jewelry, gemstones have important industrial applications. Gemstones include diamonds, rubies, emeralds, beryl, garnet, topaz, and zircon. Gemstones are frequently used as abrasives because they are hard minerals. For example, diamonds are used in drill bits and saws designed to cut through rock and steel Diamonds, the hardest substance on the Mohs hardness scale, can also be manufactured in the laboratory for industrial use.