Thermonatrite
Sodium carbonate monohydrate — a warm-evaporite mineral, natron's dehydrated cousin.
Intro adapted from Wikipedia (CC BY-SA).
Thermonatrite is an IMA-recognized mineral species in the carbonate class, with the chemical formula Na₂(CO₃)·H₂O.
It crystallizes in the orthorhombic crystal system (space group Pca2_1).
Key properties: Mohs hardness 1–1.5; specific gravity 2.255; Vitreous luster; refractive index 1.483; optically biaxial.
IMA symbol Tnat, grandfathered status — known before the IMA’s founding, named in 1845.
Typically on soils and deposited from saline lakes; uncommon in volcanic fumaroles; in hydrothermal veins related to carbonatites.
It is found associated with Trona, natron, halite.
Its name comes from the Greek for heat and natron, as the dehydration product from heating natron.