Encyclopedia of Global Resources part 20 provides a wide variety of perspectives on both traditional and more recent views of Earth's resources. It serves as a bridge connecting the domains of resource exploitation, environmentalism, geology, and biology, and it explains their interrelationships in terms that students and other nonspecialists can understand. The articles in this set are extremely diverse, with articles covering soil, fisheries, forests, aluminum, the Industrial Revolution, the . Department of the Interior, the hydrologic cycle, glass, and placer mineral deposits. . | 160 Calcium compounds Global Resources . Geological Survey Cadmium Statistics and Information http minerals pubs commodity cadmium See also Alloys Canada China Kazakhstan Metals and metallurgy Mexico South Korea Steel United States Zinc. Calcium compounds Category Mineral and other nonliving resources Where Found Calcium compounds are widely distributed. Naturally occurring calcareous materials include calcite aragonite chalk marble shell and coral all of which are predominantly calcium carbonate CaCO3 other common calcium-bearing minerals include fluorite CaF2 and apatite Ca PO4 CO3MF OH C1 .Prin-cipal calcium ores are limestone predominantly calcite dolostone chiefly dolomite MgCa CO3 2 and gypsum rock mostly the mineral gypsum or calcium sulfate CaSO4 all widespread sedimentar y rocks. Calcium is present in all soil most water and all plant and animal life. Primary Uses Calcium compounds are used for a variety of applications including chemical manufacture construction and agriculture. Uses for elemental calcium include metal refining alloy manufacture and uranium and plutonium processing. Technical Definition Calcium abbreviated Ca atomic number 20 is a metallic element belonging to Group IIA of the periodic table of the elements alkaline-earth metals . It is chemically similar to strontium and barium. Its average molecular weight is . Its specific gravity is at 20 Celsius its melting point is approximately 850 Celsius and its boiling point is 1 480 Celsius. Description Distribution and Forms Calcium has a cubic cr ystalline structure and is silver-white in color. It is relatively soft ductile and malleable. A chemically active element it occurs in nature only in combination with other elements. It tarnishes readily in air reacts with water to form a hydroxide and combines with oxygen carbon hydrogen chlorine fluorine phosphorus sulfur and other elements to form many compounds. Calcium is the fifth most abundant element in the .
