Bultfonteinite
| Bultfonteinite | |
|---|---|
Bultfonteinite from Shijiangshan mine, China | |
| General | |
| Category | Nesosilicates |
| Formula | Ca2SiO2(OH,F)4 |
| IMA symbol | Bul |
| Strunz classification | 9.AG.80 |
| Dana classification | 52.4.7.2 |
| Crystal system | Triclinic |
| Crystal class | Pinacoidal (1) (same H-M symbol) |
| Space group | P1 |
| Unit cell | a = 10.99 Å, b = 8.18 Å c = 5.67 Å, α = 93.95° β = 91.32°, γ = 89.85°; Z = 4 |
| Identification | |
| Color | Colorless, pink, light brown |
| Twinning | Interpenetrating on {100} and {010}; polysynthetic |
| Cleavage | Good on {100} and {010} |
| Fracture | Conchoidal |
| Mohs scale hardness | 4.5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.587 nβ = 1.590 nγ = 1.597 |
| Birefringence | δ = 0.010 |
| 2V angle | 70° (measured) |
| Dispersion | r > v; barely perceptible |
| Solubility | Soluble in hydrochloric acid |
| References | |
Bultfonteinite, originally dutoitspanite, is a pink, light-brown or colorless mineral with chemical formula Ca2SiO2(OH,F)4. It was discovered in 1903 or 1904 in the Bultfontein mine in South Africa, for which the mineral is named, and described in 1932.