Map Of gypsum deposits in northern Ohio, black squares point out The placement of deposits, from "Geography of Ohio", 1923 Gypsum is used in a wide variety of apps: Impurities in refinery gypsum squander have, in several circumstances, prevented them from getting used as ordinary gypsum in fields for instance https://www.propanraya.com/id/produk/eco-gypsum-ee-4050