Trona << TROH nuh >> is a gray, white, or yellowish-white mineral that contains sodium carbonate, sodium bicarbonate, and water. It forms from ground water that dissolves sodium in rocks. Some of the sodium-rich water pools underground or on Earth’s surface. As the water evaporates, trona crystals form. The crystals appear as fibrous (threadlike) or columnar (columnlike) structures in rock layers or in thick beds deposited by modern or ancient saltwater lakes. Deposits near the surface occur only in dry areas because rain water rapidly dissolves trona.
Trona is a major source of sodium carbonate or soda ash, a chemical used in the making of glass, paper, soap, and water softeners. Trona can be mined or produced artificially by evaporating seawater. The world’s largest pure deposit of trona lies underground near Green River, Wyoming. Major trona deposits also occur in Botswana, Mexico, and Turkey.
See also Soda; Wyoming (The mid-1900’s).
