Ullmannite
| Ullmannite | |
|---|---|
| General | |
| Category | Sulfide mineral |
| Formula | NiSbS |
| IMA symbol | Ull |
| Strunz classification | 2.EB.25 |
| Crystal system | Cubic |
| Crystal class | Tetartoidal (23) H-M symbol: (23) |
| Space group | P213 |
| Unit cell | a = 5.91(2) Å; Z = 4 |
| Identification | |
| Color | Steel-gray to tin white |
| Twinning | Penetration twins about [110] |
| Cleavage | Perfect on {001} |
| Fracture | Uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 5–5.5 |
| Luster | metallic |
| Diaphaneity | Opaque |
| Specific gravity | 6.65–6.85 |
| References | |
Ullmannite or Nickel glance (trivial name) is a nickel antimony sulfide mineral with formula: NiSbS. Considerable substitution occurs with cobalt and iron in the nickel site along with bismuth and arsenic in the antimony site. A solid solution series exists with the high cobalt willyamite.