Inclusions: Purely natural gypsum crystals often contain inclusions, that happen to be foreign minerals or components trapped in the crystal framework for the duration of development. Widespread inclusions in gypsum is usually clay minerals, iron oxides that cause coloration, as well as tiny gas bubbles. Calcination: The rock is heated https://www.propanraya.com/id/produk/eco-gypsum-ee-4050