Nissonite
| Nissonite | |
|---|---|
 Nissonite from Iron Monarch open cut, Iron Knob, Middleback Range, Eyre peninsula, South Australia, Australia | |
| General | |
| Category | Phosphate mineral |
| Formula (repeating unit) | Cu2Mg2(PO4)2(OH)2·5H2O |
| Strunz classification | 8.DC.05 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | C2/c |
Nissonite is a very rare copper phosphate mineral with formula: Cu2Mg2(PO4)2(OH)2·5H2O. It crystallizes in the monoclinic crystal system typically as crusts, tabular crystals, and diamond-shaped crystals. The color is blue-green. It has a light green streak, a Mohs hardness of 2.5 and a specific gravity of 2.73. Cleavage is {100} distinct.
Nissonite was discovered in 1966 and was named after William H. Nisson (1912–1965). It is from Llanada copper mine, near Llanada, San Benito Co., California.