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Gypsum was known in Old English as spærstān, "spear stone", referring to its crystalline projections. Thus, the word spar in mineralogy, by comparison to gypsum, refers to any non- ore mineral or crystal that forms in spearlike projections.
Various sized cuts of 1 ⁄ 2 in (13 mm) drywall with tools for maintenance and installation . Drywall (also called plasterboard, dry lining, [1] wallboard, sheet rock, gib board, gypsum board, buster board, turtles board, slap board, custard board, gypsum panel and gyprock) is a panel made of calcium sulfate dihydrate (), with or without additives, typically extruded between thick sheets of ...
A restored gesso panel representing St. Martin of Tours, from St. Michael and All Angels Church, Lyndhurst, Hampshire. Gesso (Italian pronunciation:; 'chalk', from the Latin: gypsum, from Greek: γύψος), also known as "glue gesso" or "Italian gesso", [1] is a white paint mixture used to coat rigid surfaces such as wooden painting panels or masonite as a permanent absorbent primer substrate ...
USG has a large gypsum plant located 17 miles (27 km) west of El Centro, California, along highway Interstate 8, at Plaster City. [25] The Plaster City location makes Sheetrock brand gypsum panels. The gypsum is mined from a quarry located 20 miles (32 km) to the north, in the Fish Creek Mountains of Imperial County. The quarry is estimated to ...
A gypsum block is made of gypsum plaster and water. The manufacturing process [1] is automated at production plants where raw gypsum (CaSO 4 ·2H 2 O) is ground and dried, then heated to remove three-quarters of the bound water and thus transformed into calcium sulfate hemihydrate (CaSO 4 ·½H 2 O), also known as gypsum plaster, stucco, calcined gypsum or plaster of Paris.
Selenite, satin spar, desert rose, and gypsum flower are crystal habit varieties of the mineral gypsum.. All varieties of gypsum, including selenite and alabaster, are composed of calcium sulfate dihydrate (meaning that it has two molecules of water), with the chemical formula CaSO 4 ·2H 2 O. Selenite contains no selenium, the similar names both derive from Greek selḗnē (σελήνη 'Moon').
Plaster was first used as a building material and for decoration in the Middle East at least 7,000 years ago. In Egypt, gypsum was burned in open fires, crushed into powder, and mixed with water to create plaster, used as a mortar between the blocks of pyramids and to provide a smooth wall facing.
Black alabaster is a rare anhydrite form of the gypsum-based mineral. The black form is found in only three veins in the world, one each in United States, Italy, and China. Alabaster Caverns State Park, near Freedom, Oklahoma, is home to a natural gypsum cave in which much of the gypsum is in the form of alabaster. There are several types of ...