Inclusions: Normal gypsum crystals frequently contain inclusions, which can be international minerals or materials trapped throughout the crystal framework during formation. Typical inclusions in gypsum may be clay minerals, iron oxides that cause coloration, or maybe little gas bubbles. Gypsum happens in extensive beds associated with other evaporite minerals (e.g., https://www.propanraya.com/id/produk/eco-gypsum-ee-4050