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Rock Gypsum, a Triassic evaporite deposit from Nottinghamshire, U.K. Specimens are supplied in labelled card trays.
Gypsum is composed of calcium sulphate dihydrate CaSO4·2H2O . the name is derived from the Greek "Gypsos" meaning "chalk or plaster" It forms as an evaporite deposit associated with sedimentary rocks. Gypsum is deposited from lake & sea water but also from hot springs associated with volcanic activity. Pure gypsum is normally white but impurities give it a variety of hues. It is mined extensively for the manufacture of plaster, plaster board, fertilizer & soil conditioner. This example is from the Triassic deposits of Nottinghamshire, U.K. Each specimen is supplied in a labelled card tray