Nissonite Locality: Iron Monarch open cut, Iron Knob , Middleback Range, Eyre peninsula , South Australia , Australia ( Locality at mindat.org ) Field of view 4 mm. Specimen and photo Leon Hupperichs. My thanks to Volker Hoppe for this exchange specimen. — Photo: Leon Hupperichs · CC BY-SA 3.0
Nissonite
A very rare copper-magnesium phosphate forming crusts and diamond-shaped monoclinic crystals.
Intro adapted from Wikipedia (CC BY-SA).
Nissonite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Cu₂Mg₂(PO₄)₂(OH)₂·5H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c).
Key properties: Mohs hardness 2.5; specific gravity 2.73; optically biaxial.
IMA symbol Nss, IMA status: approved, named in 1966.
Found as a very rare mineral in a copper prospect (Panoche Valley, California, USA); in a Precambrian sedimentary iron deposit (Iron Monarch quarry, Australia).
It is found associated with Malachite, azurite, libethenite, turquoise, chrysocolla, cuprite, barite, calcite, gypsum, riebeckite (Panoche Valley, California, USA); malachite, calcite.
The mineral was named to honor William H. Nisson (1912–1965), amateur mineralogist, mineral collector and dealer, of Petaluma, California, USA, who first noted the mineral.