Several white microcrystals of the zinc phosphate mineral spencerite from the type locality and only one of the three known localities worldwide: Hudson Bay Mine, Salmo, Nelson Mining Division, British Columbia, Canada. — Photo: David Hospital · CC BY-SA 4.0
Spencerite
Spencerite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Zn₄(PO₄)₂(OH)₂·3H₂O.
It crystallizes in the monoclinic crystal system (space group P2/c).
Key properties: Mohs hardness 3; specific gravity 3.12–3.15; Vitreous, pearly on cleavages luster; optically biaxial.
IMA symbol Scrt, grandfathered status — known before the IMA’s founding, named in 1916.
Found as a rare secondary mineral in some zinc-bearing hydrothermal deposits.
It is found associated with Hemimorphite, hopeite, smithsonite, cerussite.
The mineral was named to honor Leonard James Spencer (1870–1959), British mineralogist, formerly Keeper of Minerals, British Museum (Natural History), London, England.