Kurnakovite
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| Kurnakovite | |
|---|---|
 Kurnakovite from Boron, California | |
| General | |
| Category | Nesoborates |
| Formula | MgB3O3(OH)5·5H2O |
| IMA symbol | Kko[1] |
| Strunz classification | 6.CA.20 |
| Crystal system | Triclinic |
| Crystal class | Pinacoidal (1) (same H-M symbol) |
| Space group | P1 |
| Unit cell | a = 8.3479(1) b = 10.6068(1) c = 6.4447(1) [Å] α = 98.846°, β = 108.981° γ = 105.581°; Z = 2 |
| Identification | |
| Color | White; colorless in transmitted light |
| Crystal habit | Aggregates of prismatic crystals |
| Twinning | Twinning uncommon |
| Cleavage | Poor to indistinct on {010} |
| Mohs scale hardness | 2+1⁄2 – 3 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 1.847 – 1.852 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.488 – 1.491 nβ = 1.508 – 1.510 nγ = 1.515 – 1.525 |
| Birefringence | δ = 0.027 – 0.034 |
| 2V angle | Measured: 60° to 80° |
| References | [2][3][4] |
Kurnakovite is a hydrated borate of magnesium with the chemical composition MgB3O3(OH)5·5H2O. It is a member of the inderite group and is a triclinic dimorph of the monoclinic inderite.[3]
