Inclusions: Natural gypsum crystals typically comprise inclusions, which are foreign minerals or elements trapped throughout the crystal construction for the duration of development. Popular inclusions in gypsum may be clay minerals, iron oxides that induce coloration, as well as tiny fuel bubbles. Calcination: The rock is heated in kilns at https://www.propanraya.com/id/produk/eco-gypsum-ee-4050