Gypsum is a soft mineral, hydrous calcium sulfate. Gypsum is the standard for hardness degree 2 on the Mohs mineral hardness scale. Your fingernail will scratch this mineral—that's the simplest way to identify gypsum. Gypsum also forms concretions of selenite blades called desert roses or sand roses, growing in sediments that are subjected to concentrated brines. The crystals grow from a central point, and the roses emerge when the matrix weathers away.
Size: 5.1 x 5.1 x 3.1c m.
Location: Chihuahua, Mexico