Benstonite
Benstonite is a mineral with formula Ba6Ca6Mg(CO3)13. Discovered in 1954, the mineral was described in 1961 and named after Orlando J. Benston (1901–1966).
| Benstonite | |
|---|---|
Benstonite with calcite | |
| General | |
| Category | Carbonate minerals |
| Formula (repeating unit) | Ba6Ca6Mg(CO3)13 |
| IMA symbol | Ben |
| Strunz classification | 5.AB.55 |
| Dana classification | 14.2.3.1 |
| Crystal system | Trigonal |
| Crystal class | Rhombohedral (3) H-M group: (3) |
| Space group | R3 |
| Unit cell | a = 18.280 Å, c = 8.652 Å; Z = 3 |
| Identification | |
| Color | Snow-white, ivory, very pale yellow, pale yellowish brown |
| Cleavage | Good on {3142} |
| Mohs scale hardness | 3–4 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Translucent |
| Optical properties | Uniaxial (−) |
| Refractive index | nω = 1.690 nε = 1.527 |
| Birefringence | δ = 0.163 |
| Ultraviolet fluorescence | Red or yellow under UV and X-rays |
| References | |
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