gypsum
Word family adjectivegypseousgypsiferousnoungypsum
gyp·sum /ˈdʒɪpsəm/ noun [uncountableU] 
a soft white substance that is used to make plaster of Paris 石膏
a soft white substance that is used to make plaster of Paris 石膏Examples from the Corpus
gypsum• The calcium sulphate was probably concentrated by evaporation of shallow lakes, though wind-borne gypsum dust may have contributed in places.• A small, white-backed lizard waddled and hopped across the hot gypsum, moving away from us.• Its walls and floor were sheathed in gypsum slabs, whilst its ceiling was painted blue and supported by a gypsum pillar.• Glassy sheets of gypsum crumble out of the bluffs.• A cellulose-based paste is being applied to the gypsum deposits followed by a micro-sanding with fine alumina powder.• The winds over the dunes were constant, and they peppered us with the gypsum sand.• The gypsum crust is more soluble than the limestone so it is quite rapidly weathered by rainwater.• It was brackish, laced with gypsum, but she forced it down, and she filled the bottles.
(1300-1400) Latin Greek gypsos