| Calciborite | |
| Category: | Inoborates |
| Formula: | CaB2O4 |
| Imasymbol: | Cbo[1] |
| Molweight: | 125.70 g/mol |
| Strunz: | 6.BC.10 |
| System: | Orthorhombic |
| Class: | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Symmetry: | Pccn |
| Unit Cell: | a = 8.38 Å, b = 13.82 Å, c = 5.00 Å; Z = 8 |
| Color: | White |
| Habit: | Prismatic crystals and radial clusters |
| Cleavage: | None |
| Fracture: | Conchoidal to uneven |
| Mohs: | 3.5 |
| Luster: | Vitreous |
| Refractive: | nα = 1.595 nβ = 1.654 nγ = 1.670 |
| Opticalprop: | Biaxial (-) |
| Birefringence: | δ = 0.075 |
| 2V: | Measured: 54° |
| Streak: | White |
| Gravity: | 2.878 |
| Diaphaneity: | Translucent |
| References: | [2] [3] [4] [5] |
Calciborite, CaB2O4, is a rare calcium borate mineral.
It was first described in 1955 in the Novofrolovskoye copper–boron deposit, near Krasnoturinsk, Turinsk district, Northern Ural Mountains, Russia.[4] 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.[5] It has also been reported from the Fuka mine of Okayama Prefecture, Japan.[4]