Inyoite
| Inyoite | |
|---|---|
|  | |
| General | |
| Category | Nesoborates | 
| Formula (repeating unit) | CaB3O3(OH)5·4H2O | 
| Strunz classification | 6.CA.35 | 
| Crystal system | Monoclinic | 
| Crystal class | Prismatic (2/m) H-M symbol: (2/m) | 
| Space group | P21/a | 
| Unit cell | a = 10.63, b = 12.06 c = 8.4 [Å]; β = 114.03°; Z = 4 | 
| Identification | |
| Colour | Colourless, white on dehydration. | 
| Crystal habit | Commonly as prismatic to tabular crystals; also in cockscomb aggregates of pseudorhombohedral crystals; coarsely spherulitic or granular | 
| Cleavage | Good on {001}, distinct on {010} | 
| Fracture | Irregular/uneven | 
| Tenacity | Brittle | 
| Mohs scale hardness | 2 | 
| Lustre | Vitreous | 
| Specific gravity | 1.875 | 
| Optical properties | Biaxial (-) | 
| Refractive index | nα = 1.495 nβ = 1.505 - 1.512 nγ = 1.520 | 
| Birefringence | Maximum δ = 0.025 | 
| Dispersion | Weak | 
| References | [1][2] | 
Inyoite, named after Inyo County, California, where it was discovered in 1914, is a colourless monoclinic mineral. It turns white on dehydration. Its chemical formula is Ca(H4B3O7)(OH)·4H2O or CaB3O3(OH)5·4H2O.[2]

Inyoite, 3 cm. crystal, from Monte Azul deposit, Sijes, Salta Province, Argentina.
References
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