Hambergite

Hambergite
2.3 x 1.1 x 1 cm crystal of hambergite on albite from Paprok, Nuristan Province, Afghanistan
General
Category Borate mineral
Formula
(repeating unit)		 Be2BO3OH
Strunz classification 6.AB.05
Crystal system Orthorhombic
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space group Pbca
Unit cell a = 9.71, b = 12.2
c = 4.42 [Å]; Z = 8
Identification
Color Colorless, pale gray, pale yellow
Crystal habit Prismatic crystals
Twinning On {110}
Cleavage Perfect on {010}, good on {100}
Tenacity Brittle
Mohs scale hardness 7.5
Luster Vitreous
Streak White
Diaphaneity Transparent to translucent
Specific gravity 2.347–2.372
Optical properties Biaxial (+)
Refractive index nα = 1.554 - 1.560 nβ = 1.587 - 1.591 nγ = 1.628 - 1.631
Birefringence δ = 0.074
2V angle 87°
References [1][2][3]

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.[2][3][1]

Tabular, terminated crystal from the Gem Hill, Mesa Grande District, San Diego County, California (size: 1.5 x .8 x .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.[1]

It was first described by mineralogist and geographer W. C. Brøgger in 1890.[4] The type locality is Salbutangen, Helgeroa, Langesundsfjorden, Larvik, Vestfold, Norway where it was found in a pegmatite dike of nepheline syenite composition.[2][5]

References

  1. 1 2 3 "Hambergite" (PDF). Mineral Data Publishing. Retrieved 6 January 2012.
  2. 1 2 3 "Hambergite". mindat.org. Retrieved 6 January 2012.
  3. 1 2 "Hambergite Mineral Data". Retrieved 6 January 2012.
  4. ↑ Godal, Anne Marit (ed.). "hambergitt". Store norske leksikon (in Norwegian). Norsk nettleksikon. Retrieved 6 January 2012.
  5. ↑ Mindat location data


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