Abstract/Description: CaSO4-2H2O - Mohs Hardness: 2. Fine Gypsum specimens are very popular among mineral collectors, especially the varieties Selenite and Desert Rose. Stand-alone, perfect Selenite crystals come from Ellsworth, Mahoning Co., Ohio. Curved Gypsum crystals and Gypsum Flowers exist in the Mammoth Caves of Kentucky, and large crystals of Selenite have come from Hanksville, Utah.
Subject(s): environmental sciences