[jip-suh
m] 
| a very common mineral, hydrated calcium sulfate, CaSO4·2H2O, occurring in crystals and in masses, soft enough to be scratched by the fingernail: used to make plaster of Paris, as an ornamental material, as a fertilizer, etc. |
| gyp·sum (jĭp'səm) n. A widespread colorless, white, or yellowish mineral, CaSO4·2H2O, used in the manufacture of plaster of Paris, various plaster products, and fertilizers. [Middle English gipsum, from Latin gypsum, from Greek gupsos, probably of Semitic origin; akin to Arabic jibs, jiṣṣ, jaṣṣ, from Akkadian gaṣṣu.] |
