Selenite is a crystallized form of Gypsum, which is used for good luck and protection. It is mineral specimen that has a pearl-like luster and has been described as having a moon-like glow. The word selenite comes from the greek word for Moon, and means Moon rock.
You will receive a similar piece to the one pictured. Each piece is approximately 1" wide and 4-5" long. Please see the last picture for a size reference.