Genthelvite Locality: Huanggang Fe-Sn deposit (Huanggangliang Mine; Huanggang Mine), Hexigten Banner (Keshiketeng Co.), Ulanhad League (Chifeng Prefecture), Inner Mongolia Autonomous Region, China Original description: Small cluster of lustrous pink/brown genthelvite crystals, 18 x 18 x 14 mm. K. Nash specimen and photo. — Photo: Kelly Nash · CC BY 3.0
Genthelvite
Genthelvite is an IMA-recognized mineral species in the silicate class, with the chemical formula Be₃Zn₄(SiO₄)₃S.
It crystallizes in the cubic crystal system (space group P-43n). It is a member of the Cancrinite-sodalite, Sodalite structural group.
Key properties: Mohs hardness 6.5; specific gravity 3.44–3.7; Vitreous luster.
IMA symbol Ghv, grandfathered status — known before the IMA’s founding, named in 1944.
Found in miarolitic cavities in granite pegmatites; in alkaline granites and syenites, greisens, and skarns.
It is found associated with Phenakite, bertrandite, hambergite, siderite, sphalerite, willemite, gahnite, topaz, zircon, quartz, microcline, zeolites.
The prefix for Frederick August Ludwig Karl Wilhelm Genth (1820–1893), German-American mineralogist, who described a zinc-rich helvite (danalite), later renamed genthelvite.