Wülfingite - Germany, Saxony-Anhalt, Hettstedt, Gottesbelohnungshütte - 1,5 mm. Photos from tomeikminerals.com can be used under a Creative Commons Licenese 4.0 CC-BY, as explained in: https://www.tomeikminerals.com/about-me . — Photo: Henk Smeets - Tomeik Minerals · CC BY 4.0
Wülfingite
Wülfingite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Zn(OH)₂.
It crystallizes in the orthorhombic crystal system (space group P2_12_12_1). It is a member of the Cristobalite structural group.
Key properties: Mohs hardness 3; specific gravity 3.05; White streak; Waxy luster; optically biaxial.
IMA symbol Wfg, IMA status: approved, named in 1983.
A rare secondary mineral formed by weathering of zinc-bearing slag (Richelsdorf, Germany).
It is found associated with Simonkolleite, hydrocerussite, diaboleite, zincite, hydrozincite, zinc (Richelsdorf, Germany); ashoverite, fluorite (near Ashover, England).
The mineral was named to honor Dr. Ernst Anton Wülfing (1860–1930), Professor of Mineralogy and Petrography, Heidelberg University, Heidelberg, Germany.