Selenite is a variety of gypsum. which is readily cleaved into natural wands or sheets. It is a very soft stone which can be scratched easily with a fingernail.
The name selenite comes from the Greek word Selene, meaning moon. It has been used for window panes, such as those in Santa Sabina in Rome. The giant crystals in the Naica Cave of Crystals are Selenite Gypsum.
These selenite wands are roughly 8" long and range from 1/2" to 3/4" thick by 1/2" to 3/4" wide. They weigh between 3-4 oz each.