Blue crystal aggregates of namuwite on matrix from Germany (Herzog Julius Smelter Slag Locality, Astfeld, Goslar, Lower Saxony, Germany). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Namuwite
Namuwite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Zn₄(SO₄)(OH)₆·4H₂O.
It crystallizes in the hexagonal crystal system (space group P-3). It is a member of the Ktenasite structural group.
Key properties: Mohs hardness 2; specific gravity 2.77; Very pale green streak; Pearly luster.
IMA symbol Nmw, IMA status: approved, named in 1981.
An uncommon secondary mineral formed in the oxidized zone of hydrothermal Cu–Zn bearing mineral deposits; may be derived from metallic slags.
It is found associated with Hydrozincite, schulenbergite, serpierite, ktenasite, devilline, gypsum.
The name refers to the NAtional MUseum of Wales, Cardiff, Wales, in the collection of which the type specimen was noted.