Kurnakovite | |
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![]() Kurnakovite from Boron, California | |
General | |
Category | Nesoborates |
Formula (repeating unit) | 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]