(d) Gypsum is not found in Uttar Pradesh. Gypsum is a soft sulphate mineral composed of calcium sulphate dihydrate, with the chemical formula CaSO4.2H2O. it is widely mined and is used as a fertiliser, and as the main constituent in many forms of plaster, blackboard chalk and wallboard. Rajasthan state is the largest producer of gypsum in India.