MINERALS GYPSUM, ANHYDRITE, PLASTERS Gypsum is a mineral containing calsium sul fate in its chemical composition. In addition to natural Gypsum, synthetic gypsum is pro duced as well. Important gypsum sources include ankm orum, Yozgat, Erzincan, Ankara-Bala, Sivas, Kars-Kağızman, Tuzluca, Denizli-Sarayköy and Niğde-Karakol.