hambergite

{{infobox mineral | name = Hambergite | image = File:Hambergite-rare-09-15a.jpg | imagesize = 260px | alt = | caption = 2.3 × 1.1 × 1 cm crystal of hambergite on albite from Paprok, Nuristan Province, Afghanistan | category = Borate mineral | formula = Be2BO3OH | IMAsymbol = Hb | molweight = | strunz = 6.AB.05 | dana = | system = Orthorhombic | class = Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) | symmetry = Pbca | unit cell = a = 9.76, b = 12.20 c = 4.43 [Å]; Z = 8 | color = Colorless, pale gray, pale yellow | colour = | habit = Prismatic crystals | twinning = On {110} | cleavage = Perfect on {010}, good on {100} | fracture = | tenacity = Brittle | mohs = 7.5 | luster = Vitreous | streak = White | diaphaneity = Transparent to translucent | gravity = 2.347–2.372 | density = | polish = | opticalprop = Biaxial (+) | refractive = nα = 1.554 – 1.560 nβ = 1.587 – 1.591 nγ = 1.628 – 1.631 | birefringence = δ = 0.074 | pleochroism = Colorless | 2V = 87° | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = Soluble in HF (Hydrogen fluoride) | impurities = | alteration = | other = | prop1 = | prop1text = | references = }} Hambergite (Be2BO3OH) is a beryllium borate mineral named after Swedish explorer and mineralogist Axel Hamberg (1863–1933). The mineral occurs as white or colorless orthorhombic crystals. thumb|left|Tabular, terminated crystal from the Gem Hill, Mesa Grande District, San Diego County, California (size: 1.5 × .8 × .5 cm)

==Occurrence== Hambergite occurs in beryllium bearing granite pegmatites as a rare accessory phase. It occurs associated with beryl, danburite, apatite, spodumene, zircon, fluorite, feldspar and quartz.