Density and Precise Gravity: Density refers back to the mass per unit volume of a material, while unique gravity compares a mineral's density into the density of drinking water. Gypsum occurs in considerable beds related to other evaporite minerals (e.g., anhydrite and halite), particularly in Permian and Triassic sedimentary formations; https://www.propanraya.com/id/produk/eco-gypsum-ee-4050