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 | 06.AB.05 |
| Crystal symmetry |
Orthorhombic, dipyramidal H-M symbol: (2/m 2/m 2/m) Space group: P bca |
| Unit cell | a = 9.71 Å, b = 12.2 Å, c = 4.42 Å; Z=8 |
| Identification | |
| Color | Colorless, pale gray, pale yellow |
| Crystal habit | Prismatic crystals |
| Crystal system | Orthorhombic |
| 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 2 3 "Hambergite" (PDF). Mineral Data Publishing. Retrieved 6 January 2012.
- 1 2 3 "Hambergite". mindat.org. Retrieved 6 January 2012.
- 1 2 "Hambergite Mineral Data". Retrieved 6 January 2012.
- ↑ Godal, Anne Marit (ed.). "hambergitt". Store norske leksikon (in Norwegian). Norsk nettleksikon. Retrieved 6 January 2012.
- ↑ Mindat location data
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