Koritnigite
Koritnigite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Zn(AsO₃OH)·H₂O.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Koritnigite structural group.
Key properties: Mohs hardness 2; specific gravity 3.54; Pearly on {010} luster; optically biaxial.
IMA symbol Kor, IMA status: approved, named in 1978.
A secondary mineral of the lower oxidation zone in a dolostone-hosted polymetallic hydrothermal ore deposit (Tsumeb, Namibia).
It is found associated with Tennantite, cuprian adamite, stranskiite, lavendulan, köttigite, tsumcorite, prosperite, o’danielite (Tsumeb, Namibia); erythrite, arsenolite.
The mineral was named to honor Professor Sigmund Koritnig (1912–1984), petrologist, University of Göttingen, Göttingen, Germany.