Trona Locality: Owens Lake , Owens Valley , Inyo County , California , USA ( Locality at mindat.org ) Size: 14.4 x 10.8 x 7.8 cm Trona is a rare carbonate found in saline lakes and their evaporites. This is a superb, large example of sugary, translucent, honey-brown crystals of large size. Such specimens from this locale are considered to be the finest examples of the species. From a small find. Ex. Karl Faddis Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Trona
Sodium sesquicarbonate — a non-marine evaporite, and America's chief source of soda ash.
Intro adapted from Wikipedia (CC BY-SA).
Trona is an IMA-recognized mineral species in the carbonate class, with the chemical formula Na₃(HCO₃)(CO₃)·2H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c).
Key properties: Mohs hardness 2.5–3; specific gravity 2.11; Vitreous luster; refractive index 1.481; optically biaxial.
IMA symbol Tn, grandfathered status — known before the IMA’s founding, named in 1773.
Deposited from saline lakes and along river banks as efflorescences in arid climates; rarely from fumarolic action.
It is found associated with Natron, thermonatrite, halite, glauberite, thénardite, mirabilite, gypsum (alkali lakes); shortite, northupite, bradleyite, pirssonite (Green River Formation.
A short form of the Arabic word for the natural compound.