| Talnakhite | |
| Category: | Sulfide mineral |
| Formula: | Cu9(Fe, Ni)8S16 |
| Imasymbol: | Tlk[1] |
| Strunz: | 2.CB.10b |
| System: | Isometric |
| Class: | Hextetrahedral (3m) H-M symbol: (3m) |
| Symmetry: | I 3m |
| Color: | Brass-yellow, tarnishes to pink or brown tints, then iridescent |
| Luster: | Metallic |
| Diaphaneity: | Opaque |
Talnakhite is a mineral of chalcopyrite group with formula: Cu9(Fe, Ni)8S16.[2] It was named after the Talnakh ore deposit, near Norilsk in Western Siberia, Russia where it was discovered as reported in 1963 by I. Budko and E. Kulagov.[3] It was officially named "talnakhite" in 1968.[4] [5] Despite the initial announcement it turned out to be not a face centered high-temperature polymorph of chalcopyrite, but to have composition Cu18(Fe, Ni)18S32. At 80°C to 100°C it decomposes to tetragonal cubanite plus bornite.[6] [7]