Selenite is a specific variety of the mineral gypsum named after the Ancient Greek goddess of the moon, Selene. The Greeks especially appreciated the beauty of selenite, even making windows with the stone. This gemstone received its official name from J.G. Wallerius in 1747 when he wrote Mineralogia, eller Mineralriket.
Gypsum as a general material has been valued since as far back as the Egyptians where it was used for decorative purposes. One unique use of selenite is in the Santa Sabina church in Rome: the large arched windows (built in the 5th century) are made of sheets of selenite, not glass. After large amounts of gypsum were found near Paris, France, a material known as Plaster of Paris was created. Plaster of Paris is gypsum that has been chemically altered to extract the water within. It's also said French farmers used raw gypsum as a soil additive.
 
The gemstone selenite is most closely associated with the crown chakra, which represents wisdom and spirituality, as well as the third eye chakra. The colorless beauty and translucency of selenite is often attributed to purity and peace in both metaphysical beliefs and color theory. Selenite is excellent to use when meditating or trying to achieve mental clarity, as it is believed to compel the person holding it to be honest with themselves.
 
Selenite is considered a high-energy crystal that vibrates at a high frequency. Despite being an incredibly soft stone, so soft a fingernail can scratch it, selenite gemstones are believed to be a stone of protection that wards the mind. It is commonly used by crystal practitioners as a way to cleanse the body, mind and spirit of negativity and self-limitation--as well as cleansing other gemstones being used in healing practices.