Selenite is a Crystalline variety of Gypsum. It is often transparent and colorless. If the Selenite Crystals show translucency, opacity and/or color, it is caused by the presence of other minerals and many be “druzy”. Selenite often appears to have a “cat’s eye” appearance especially with the polished variety. It will often magnify images when the translucency is very clear. An all time favorite at the Rock Shop.