Gypsum Are available in hydrothermal veins, that are fractures in rocks filled with mineral-rich fluids that originate from deep within the Earth's crust. Map of gypsum deposits in northern Ohio, black squares reveal The situation of deposits, from "Geography of Ohio", 1923 Gypsum is used in a wide variety of https://www.propanraya.com/id/produk/eco-gypsum-ee-4050