Skip to content
Earth & SkyGreekEnglish

Selenite

/ˈsɛlɪnaɪt/noun

The transparent crystalline form of gypsum, splitting into clear sheets.

The Greek roots

σελήνη
selḗnē
moon
+
-ίτης
-ítēs
stone of

Literally: moonstone

The story of the word

Greek writers called it λίθος σεληνίτης, moon-stone, from the pale sheen of a cleaved sheet; some later authors claimed it waxed and waned with the moon. Before window glass was cheap, thin selenite panes glazed Roman and medieval windows and let in a milky light. The element selenium got the same goddess for a different reason: Berzelius named it as the moon to tellurium's earth.

How it travelled
Ancient Greek → Latin → English
First recorded
17th century

Same family

seleniumselenographySelene

In a sentence

Cave of the Crystals holds selenite beams eleven metres long.

She split the selenite with a fingernail and it came away in a clear sheet.

Built on the same root

More from Earth & Sky