Selenite, a crystallized form of gypsum, which chemically, it is a hydrous calcium sulfate.
The name 'selenite' is mostly synonymous with gypsum but has been used historically to describe the transparent variety, as opposed to satin spar gypsum for the fibrous variety and alabaster for the fine-grained massive form. [mindat]
According to lore, Selenite is named for Selene, a Titan goddess in Greek mythology, daughter of the Titans Hyperion and Theia. She had two siblings, Helios and Eos. She was the goddess of the moon, which she drove every night across the skies. Selene was linked to Artemis as well as Hecate; all three were considered lunar goddesses.
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