a sodium calcium sulfate mineral (CaSO•2H O), colorless, white, or yellowish, found in powder or crystal form. Used for plaster, cement, and medicinal purposes; thought to be mined by Native Americans. Found in dry sections of Mammoth Cave, where it precipitates from the walls in the form of gypsum "flowers."
(gyp'-sum) A monoclinic mineral (CaSO4 .2H2O) that is colorless to white in crystals but gypsum in massive beds may range from red to yellow to brown, gray, or black. It is the most common natural sulfate mineral. Gypsum defines 2 on the Mohs hardness scale. It is commonly associated with rock salt (halite) and anhydrite and forms beds and lenses interstratified with limestone, shale, and clay, especially in rocks of Permian to Triassic age. Gypsum also occurs in volcanic fumarolic deposits and as an accessory mineral in metalliferous veins.
A hydrated calcium sulfate (CaSO42H20). It is formed naturally as the result of the reaction of sulfuric acid produced by the decomposition of pyrite upon the calcium carbonate of shells existing in clay. A sedimentary rock.
Hydrated calcium sulfate (CaSO4.2H20), mainly used as a soil conditioner. Either mined from natural sources or produced as a by-product of the manufacture of phosphoric acid, the latter being known as phosphogypsum.
is hydrous calcium sulfate. It is a common mineral used as an ingredient in many casting materials, including Plaster of Paris. It can be made weather resistant by formulating it with cement and other chemicals.
gypsum is made of calcium sulfate and is one of the more beautiful mineral decorations. The snowy white gypsum can grow in swordlike needles (up to 30 inches), flower shapes, tendrils, or sheets covering ceilings, walls, or floors.
Hydrated Calcium Sulphate. Can form when limestone is attacked by sulphuric acid. The resulting product is larger than its components so can be 'squirted' through pores in the rock under pressure, whilst in crystalline form
A natural inert pigment consisting essentially of a hydrated form of calcium sulphate. When heated to remove a part of the water of hydration, "plaster of Paris" is formed. Further heating to remove all of the water of hydration produces calcium sulphate, which does not react with water to form a solid "set material" as does plaster of Paris.
Crystals of native sulphate of lime. Being subjected to a moderate heat to expel the water of crystallisation, it forms plaster of Paris, and coming in contact with water immediately assumes a solid form. Of the numerous species, alabaster is perhaps the most abundant.