|a colourless or white mineral sometimes tinted by impurities, found in beds as an evaporite. It is used in the manufacture of plaster of Paris, cement, paint, school chalk, glass, and fertilizer. Composition: hydrated calcium sulphate. Formula: CaSO4.2H2O. Crystal structure: monoclinic|
|[C17: from Latin, from Greek gupsos chalk, plaster, cement, of Semitic origin]|
|a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes.|
|a chattering or flighty, light-headed person.|
|gypsum (jĭp'səm) Pronunciation Key
A colorless, white, or pinkish mineral. Gypsum occurs as individual blade-shaped crystals or as massive beds in sedimentary rocks, especially those formed through the evaporation of saline-rich water. It is used in manufacturing plasterboard, cement, and fertilizers. Chemical formula: CaSO4·2H2O.