Wurtzite. Pen for scale. Mineral collection of Bringham Young University Department of Geology, Provo, Utah. Photograph by Andrew Silver. BYU index 2-4075b, ZnS — Photo: Andrew Silver, USGS · Public domain
Wurtzite
The hexagonal polymorph of zinc sulfide — sphalerite's high-temperature twin.
Intro adapted from Wikipedia (CC BY-SA).
Wurtzite is an IMA-recognized mineral species in the sulfide class, with the chemical formula ZnS.
It crystallizes in the hexagonal crystal system (space group P6_3mc). It is a member of the Wurtzite structural group.
Key properties: Mohs hardness 3.5–4; specific gravity 4.09; Brown streak; Resinous, brilliant submetallic on crystal faces luster; optically uniaxial.
IMA symbol Wur, grandfathered status — known before the IMA’s founding, named in 1861.
Of hydrothermal origin in veins with other sulfides. Also along shrinkage fractures in clay-ironstone concretions, of low-temperature origin.
It is found associated with Sphalerite, pyrite, chalcopyrite, barite, marcasite.
The name refers to Charles Adolphe Wurtz (1817–1884), French chemist, of Paris, France.