Nissonite

Nissonite is a very rare copper phosphate mineral with the 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
Nissonite from Iron Monarch open cut, Iron Knob, Middleback Range, Eyre peninsula, South Australia, Australia
General
Category	Phosphate mineral
Formula	Cu2Mg2(PO4)2(OH)2·5H2O
IMA symbol	Nss[1]
Strunz classification	8.DC.05
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	C2/c

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.