Hambergite

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)

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
Pleochroism	Colorless
2V angle	87°
Solubility	Soluble in HF (Hydrogen fluoride)
References	[1][2][3]

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. "Hambergite" (PDF). Mineral Data Publishing. Retrieved 6 January 2012.
2. "Hambergite". mindat.org. Retrieved 6 January 2012.
3. "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

Bibliography

• Palache, P.; Berman H.; Frondel, C. (1960). "Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)" John Wiley and Sons, Inc., New York, pp. 370–372.