Hydrokenoelsmoreite , Stolzite Seagraves Mine (Lone Star Mine; Silver King Prospect; Star Mine; Grey Eagle Mine), Seafoam District, Custer Co., Idaho, USA Locality: Seagraves Mine (Lone Star Mine; Silver King Prospect; Star Mine; Grey Eagle Mine), Seafoam District, Custer County , Idaho , USA ( Locality at mindat.org ) Size: 6.5 x 6.0 x 4.5 cm. White stolzite grains accent rich yellow veins of Hydrokenoelsmoreite (formerly known as ferritungstite) crystals (micros, but visible with a loupe) on this rare locality piece. Old material from the Pasco, Washington collection of Andrew Micklancic. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Hydrokenoelsmoreite
A colorless-to-white hydrous tungsten oxide — an isometric mineral of the pyrochlore family with a vacancy-rich formula.
Intro adapted from Wikipedia (CC BY-SA).
Hydrokenoelsmoreite is an IMA-recognized mineral species in the tungstate class, with the chemical formula ₂W₂O₆(H₂O).
It crystallizes in the cubic crystal system (space group Fd3m). It is a member of the Pyrochlore-Elsmoreite structural group.
Key properties: Mohs hardness 3; specific gravity 6.025; White streak; Vitreous luster; optically isotropic.
IMA symbol Hkm, IMA status: approved, named in 2003.
Secondary in the weathering zone of greisen vein and stockwork systems in granite.
It is found associated with Wolframite, quartz (England); quartz, white mica, cassiterite, arsenopyrite, native bismuth, chalcopyrite, ferberite, molybdenite (Elsmore, Australia).
The name refers to a member of the elsmoreite group with prefixes to indicate dominant H2O (hydro) in the Y site and essential vacancies (keno) in the A site. Suffix indicates the polytype.