thomsenolite

{{Infobox mineral | name = Thomsenolite | image = Thomsenolite and Ralstonite - Ivittuut, Arsuk Firth, Kitaa. West Greenland.jpg | alt = | caption = Thomsenolite (obelisks) and some pseudocubic ralstonite (picture center) | category = Halide minerals | formula = NaCaAlF6·H2O | IMAsymbol = Tse | molweight = | strunz = 3.CB.40 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = P21/b | unit cell = | color = Colourless, white, pale lilac; brownish or reddish tinted due to staining; colourless in transmitted light. | habit = | twinning = | cleavage = PerfectOn {001}; {110} distinct. | fracture = Irregular/ uneven | tenacity = Brittle | mohs = 2 | lustre = Vitreous, pearly | streak = White | diaphaneity = Transparent, translucent | gravity = | density = 2.981 g/cm3 | polish = | opticalprop = | refractive = | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }}

Thomsenolite is a mineral with formula: NaCaAlF6·H2O. It is an alteration product of cryolite.