Gypsum is usually a smooth sulfate mineral composed of calcium sulfate dihydrate, with the chemical system CaSO4·2H2O.[4] It can be widely mined and it is employed to be a fertilizer and as the major constituent in several varieties of plaster, drywall and blackboard or sidewalk chalk. Surface mining entails removing https://www.propanraya.com/id/produk/eco-gypsum-ee-4050