nahcolite

{{Infobox mineral | name = Nahcolite | category = Carbonate mineral | boxwidth = | boxbgcolor = | image = Nahcolite-20212.jpg | imagesize = | alt = | caption = Nahcolite from California (size: 9.5 x 8 x 4 cm) | formula = Sodium bicarbonate (NaHCO3) | IMAsymbol = Nah | molweight = | strunz = 5.AA.15 | dana = 13.01.01.01 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = P21/n | unit cell = a = 7.47, b = 9.68 c = 3.48 [Å]; β = 93.38°; Z = 4 | color = | colour = White to colourless, may be grey to brown | habit = Elongated crystals, fibrous masses, friable porous aggregates | twinning = Common on [101] | cleavage = {101} perfect, {111} good, {100} distinct | fracture = Conchoidal | tenacity = Brittle | mohs = 2.5 | lustre = Vitreous – resinous | streak = White | diaphaneity = Transparent to translucent | gravity = 2.21 | density = | polish = | opticalprop = Biaxial (−) | refractive = nα = 1.377 nβ = 1.503 nγ = 1.583 | birefringence = δ = 0.206 | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence= Short UV=blue-white cream-yellow, Long UV=cream-yellow | absorption = | melt = | fusibility = | diagnostic = | solubility = Soluble in water | other = | alteration = | references = }} Nahcolite is a soft, colourless or white carbonate mineral with the composition of sodium bicarbonate (NaHCO3) also called thermokalite. It crystallizes in the monoclinic system.

Nahcolite was first described in 1928 for an occurrence in a lava tunnel at Mount Vesuvius, Italy. Its name refers to the elements which compose it: Na, H, C, and O. It occurs as a hot spring and saline lake precipitate or efflorescence; in differentiated alkalic massifs; in fluid inclusions as a daughter mineral phase and in evaporite deposits.Nahcolite data on Webmineral