| Hambergite | |
| Category: | Borate mineral |
| Formula: | Be2BO3OH |
| Imasymbol: | Hb[1] |
| Strunz: | 6.AB.05 |
| 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 |
| Habit: | Prismatic crystals |
| Twinning: | On |
| Cleavage: | Perfect on, good on |
| Tenacity: | Brittle |
| Mohs: | 7.5 |
| Luster: | Vitreous |
| Streak: | White |
| Diaphaneity: | Transparent to translucent |
| Gravity: | 2.347–2.372 |
| 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° |
| Solubility: | Soluble in HF (Hydrogen fluoride) |
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] [4]
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.[4]
It was first described by mineralogist and geographer W. C. Brøgger in 1890.[5] The type locality is Salbutangen, Helgeroa, Langesundsfjorden, Larvik, Vestfold, Norway where it was found in a pegmatite dike of nepheline syenite composition.[2] [6]