berborite

{{Infobox mineral | name = Berborite | image = File:Berborite & Natrolite.jpg | alt = | caption = Berborite on natrolite | category = Borate minerals | formula = Be2(BO3)(OH,F)•H2O | IMAsymbol=Bbo | molweight = | strunz = 6.AB.10 | dana = 26.1.1.1 | system = 1T polytype: Trigonal 2H polytype: Hexagonal 2T polytype: Trigonal | class = 1T polytype: Pyramidal (3) 2H polytype: Pyramidal (6) 2T polytype: Ditrigonal pyramidal (3m) | symmetry = 1T polytype: P3 (no. 143) 2H polytype: P63 (no. 173) 2T polytype: P3c1 (no. 158) | unit cell = a = 4.43 Å, c = 5.34 Å; Z = 2; V = 90.76 Å3 (2H polytype) | color = Colorless | habit = | twinning = Complex | cleavage = {0001} Perfect | fracture = Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. | tenacity = | mohs = 3 | luster = Vitreous (Glassy) | streak = white | diaphaneity = Transparent | gravity = | density = 2.2 | polish = | opticalprop = Uniaxial (-) | refractive = nω = 1.580 nε = 1.485 | birefringence = δ = 0.095 | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = none | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | references = }} Berborite is a beryllium borate mineral with the chemical formula Be2(BO3)(OH,F)·(H2O). It is colorless and leaves a white streak. Its crystals are hexagonal to pyramidal. It is transparent and has vitreous luster. It is not radioactive. Berborite is rated 3 on the Mohs Scale.

Berborite occurs in 1T, 2T, 2H polytypes.