Selenite is a variety of Gypsum, a hydrous calcium sulphate mineral. It has a monoclinic crystal system and a hardness of 2. The best examples of Selenite are found in Mexico.
Metaphysically, Selenite is said to inspire one to let go of insecurities and reach for their desires, clear energy blockages, induce inner alignment, facilitate healing and auric cleansing, activate upper chakras and encourage spiritual attunement. Selenite is also believed to cleanse other crystals.