Berborite
Berborite | |
---|---|
![]() Berborite on natrolite | |
General | |
Category | Borate minerals |
Formula (repeating unit) | Be2(BO3)(OH,F)•H2O |
IMA symbol | Bbo[1] |
Strunz classification | 6.AB.10 |
Dana classification | 26.1.1.1 |
Crystal system | 1T polytype: Trigonal 2H polytype: Hexagonal 2T polytype: Trigonal |
Crystal class | 1T polytype: Pyramidal (3) 2H polytype: Pyramidal (6) 2T polytype: Ditrigonal pyramidal (3m) |
Space group | 1T polytype: P3 (no. 143) 2H polytype: P63 (no. 173) 2T polytype: P3c1 (no. 158) |
Unit cell | a = 4.43 Å, c = 5.34 Å; Z = 2; V = 90.76 Å3 (2H polytype) |
Identification | |
Color | Colorless |
Twinning | Complex |
Cleavage | {0001} Perfect |
Fracture | Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. |
Mohs scale hardness | 3 |
Luster | Vitreous (Glassy) |
Streak | white |
Diaphaneity | Transparent |
Density | 2.2 |
Optical properties | Uniaxial (-) |
Refractive index | nω = 1.580 nε = 1.485 |
Birefringence | δ = 0.095 |
Ultraviolet fluorescence | none |
References | [2][3][4][5] |
Berborite is a beryllium borate mineral with the chemical formula Be2(BO3)(OH,F)·(H2O). It is colorless and leaves a white streak. Its crystals are hexagonal to pyramidal. It is transparent and has vitreous luster. It is not radioactive. Berborite is rated 3 on the Mohs Scale.[3]
Berborite occurs in 1T, 2T, 2H polytypes.[4]
It was first described in 1967 for an occurrence in the Lupikko Mine, Ladoga Region Karelia Republic, Russia. It has also been reported from , Larvik, Vestfold, and , Langesundsfjord, Porsgrunn, Telemark, Norway.[2][4] It occurs in serpentine altered dolomite in association with skarn enriched in tungsten, strontium, beryllium and boron in the Keralia occurrence and in vugs with natrolite and thomsonite in Norway.[3][4]
References[]
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b Mindat.org http://www.mindat.org/min-629.html
- ^ a b c Webmineral.com http://www.webmineral.com/data/Berborite.shtml
- ^ a b c d Handbook of Mineralogy
- ^ Mineralienatlas
- Beryllium minerals
- Borate minerals
- Trigonal minerals
- Minerals in space group 143
- Minerals in space group 158
- Hexagonal minerals
- Minerals in space group 173
- Mineral stubs