Map Of gypsum deposits in northern Ohio, black squares show The situation of deposits, from "Geography of Ohio", 1923 Gypsum is used in lots of apps: Salt Flats: Gypsum is a typical ingredient of salt flats, which can be expansive, flat locations by using a salt crust on the surface https://www.propanraya.com/id/produk/eco-gypsum-ee-4050