Perfect sharp colorless single crystal of the rare Na-Mg mineral tychite from the TL in California (Searles Lake, San Bernardino County, California, United States of America). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Tychite
Tychite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Na₆Mg₂(CO₃)₄(SO₄).
It crystallizes in the cubic crystal system (space group Fd3). It is a member of the Northupite structural group.
Key properties: Mohs hardness 3.5–4; specific gravity 2.37–2.74; Vitreous luster.
IMA symbol Tyc, grandfathered status — known before the IMA’s founding, named in 1905.
Uncommon in lake-bed evaporite deposits.
It is found associated with Northupite, gaylussite, thénardite, schairerite, pirssonite (Searles Lake, California, USA); northupite (Katwe Lake, Uganda).
Its name comes from the Greek for good fortune, as the first and one of the last ten crystals examined were of this species, from a lot of about 5000 examined.