Backscattered electron (BSE) images of wumuite and some associated minerals. The image is published in an article distributed under the Creative Commons Attribution 4.0 License-. — Photo: Yuan Xue, Guowu Li, and Yingmei Xie · CC BY 4.0
Wumuite
Wumuite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula KAl₀.₃₃W₂.₆₇O₉.
It crystallizes in the hexagonal crystal system (space group P6/mmm).
Key properties: Mohs hardness 5–6; specific gravity 6.52; White streak; Vitreous to adamantine luster; optically uniaxial.
IMA symbol Wum, IMA status: approved, named in 2018.
Found in a biotite-quartz monzonite pluton near the contact zone with gabbro and nearby quartz-vein-type Au mineralization. Formed by metasomatic reaction of high-temperature fluids rich in W and Te with potassium feldspar in the monzonite.
It is found associated with Tewite, scheelite, alkali feldspar, biotite, clinoamphibole, ilmenite, zircon, zoisite, tourmaline, monazite-(Ce), allanite-(Ce), tellurite.
The name refers to the Wumu River.