Selenite (Gypsum) has many interesting properties, including its very unique and varied crystal habits. The name “Selenite” is typically synonymous with Gypsum, but has traditionally been used to describe the transparent/translucent specimen quality variety of Gypsum. It is also quite varied in color, but there’s a catch; Selenite is colorless to white. All of the other colors; yellow, tan, blue, pink, brown, reddish brown, gray and black (and there’s more) are all the result of various inclusions. And the luster varies as well; vitreous, sub-vitreous, pearly and silky.
The crystal system for Selenite (Gypsum) is monoclinic, commonly forming tabular (often water-clear) crystals. Other forms include prismatic, acicular, bladed, fibrous veins, scaly, grainy, lenticular (flattened nodules) and massive. Crystals may be curved, sometimes severely, creating formations that are called “Ram’s Horn”. In addition, crystals frequently twin, forming perfect v-shaped (fishtail and swallowtail) twins. Finally, an aesthetic formation known as the Selenite Desert Rose, is a rosette-shaped aggregate of Selenite blades with sand inclusions.
Selenite (Gypsum) is an extremely common mineral, found worldwide. Notable localities for quality specimens include China, Mexico, Morocco, Peru, Romania and the USA (Oklahoma, New York).