Calciborite
Calciborite, CaB2O4, is a rare calcium borate mineral.
| Calciborite | |
|---|---|
White crystals of calciborite from the type locality in Russia (Novofrolovskoye Deposit) | |
| General | |
| Category | Inoborates |
| Formula (repeating unit) | CaB2O4 |
| IMA symbol | Cbo |
| Strunz classification | 6.BC.10 |
| Crystal system | Orthorhombic |
| Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Space group | Pccn |
| Unit cell | a = 8.38 Å, b = 13.82 Å, c = 5.00 Å; Z = 8 |
| Identification | |
| Formula mass | 125.70 g/mol |
| Color | White |
| Crystal habit | Prismatic crystals and radial clusters |
| Cleavage | None |
| Fracture | Conchoidal to uneven |
| Mohs scale hardness | 3.5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Translucent |
| Specific gravity | 2.878 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.595 nβ = 1.654 nγ = 1.670 |
| Birefringence | δ = 0.075 |
| 2V angle | Measured: 54° |
| References | |
It was first described in 1955 in the Novofrolovskoye copper–boron deposit, near Krasnoturinsk, Turinsk district, Northern Ural Mountains, Russia. It occurs in a skarn deposit formed in limestone adjacent to a quartz diorite intrusive. It occurs associated with: sibirskite (another rare calcium borate mineral), calcite, dolomite, garnet, magnetite and pyroxene. It has also been reported from the Fuka mine of Okayama Prefecture, Japan.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.