Selenite (mineral) was filled with mineral-rich water that drove the crystals' growth. The largest of those crystals weighs 55 tons, is long, and is over 500,000 years old. Gypsum occurs on every continent and is the most common of all the sulfate minerals. Gypsum is formed as an evaporative mineral, frequently found in alkaline lake muds, clay beds, evaporated seas, salt flats, salt springs, and caves. It is frequently found in conjunction with other minerals such as, copper ores, sulfur and sulfides, silver, iron ores, coal, calcite, dolomite, limestone, and opal. Gypsum has been dated to almost every geologic age since the
Arizona Department of Mines and Mineral Resources May 2010. The ADMMR has no regulatory functions. Regulation of mineral exploration and mining on Arizona's state trust land is under the jurisdiction of the Minerals Section of the Arizona State Land Department. The Arizona Bureau of Mines, a separate agency formed in 1915, was a predecessor agency of the Arizona Geological Survey. Arizona Department of Mines and Mineral Resources The Arizona Department of Mines and Mineral Resources (ADMMR) is a state government agency in the U.S. state of Arizona that has the purpose of promoting and developing the state's mineral resources. The department was established in 1939 as the