| Bultfonteinite | |
|---|---|
 Bultfonteinite from Shijiangshan mine, China | |
| General | |
| Category | Nesosilicates |
| Formula (repeating unit) | Ca2SiO2(OH,F)4 |
| IMA symbol | Bul[1] |
| Strunz classification | 9.AG.80[2] |
| Dana classification | 52.4.7.2[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°;[2] 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[2] |
| Diaphaneity | Transparent |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.587 nβ = 1.590 nγ = 1.597[2] |
| Birefringence | δ = 0.010[2] |
| 2V angle | 70° (measured) |
| Dispersion | r > v; barely perceptible |
| Solubility | Soluble in hydrochloric acid[3] |
| References | [4] |
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.
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b c d e f "Bultfonteinite". Mindat. Archived from the original on November 14, 2009. Retrieved July 19, 2012.
- ^ Foshag, W. F. (January 1933). "New Mineral Names: Bulfonteinite" (PDF). American Mineralogist. 18 (1). Mineralogical Society of America: 32. Archived (PDF) from the original on 2012-07-23. Retrieved 2012-07-19.
- ^ "Bultfonteinite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Archived (PDF) from the original on August 1, 2012. Retrieved July 19, 2012.