alexandrite

Named after Alexander II of Russia +‎ -ite.

• (US) enPR: ăl'-ĭg-zăn'-drīt, IPA^(key): /ˌæl.ɪɡˈzæn.dɹaɪt/

alexandrite (countable and uncountable, plural alexandrites)

1. (mineralogy) A form of chrysoberyl that displays a colour change dependent upon the light source, along with strong pleochroism.
   • 1922, E[ric] R[ücker] Eddison, The Worm Ouroboros: A Romance, London: Jonathan Cape […], →OCLC, page 2:

     […] the body of each high seat was a single jewel of monstrous size: the left-hand seat a black opal, asparkle with steel-blue fire, the next a fire-opal, as it were a burning coal, the third seat an alexandrite, purple like wine by night but deep sea-green by day.

• David Barthelmy (1997–2026), “Alexandrite”, in Webmineral Mineralogy Database.
• “alexandrite”, in Mindat.org, Keswick, Va.: Hudson Institute of Mineralogy, 2000–2026.