Jharkhand PSC Prelim Exam 2010 Solved Paper

(3) Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula ${\mathrm{CaSO}}_4$ · $2{\mathit{H}}_2\mathit{O}$ . It is widely mined and is used as a fertilizer, and as the main constituent in many forms of plaster, blackboard chalk and wallboard.