Selenite Tumbled Stone Selenite Tumbled stone is the most common crystal cut and polished shape available. Pieces of stone have been polished to give them a smooth and shiny surface. The shape is irregular and the sizes vary in the form of a nugget. Ancient Greeks called this crystal Selenite, which means moon. Due to its translucent nature, Selenite was also once used as windows in temples and the homes of nobles because its opaque nature allowed light to shine through and disperse throughout the room.