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Formula: (K1.5☐0.5)Σ2(Te1.25W0.25☐0.5)Σ2W5O19
Composite oxide, tellurium- and
tungsten- bearing mineral
Crystal System: Orthorhombic
Specific gravity: 6.903 calculated
Hardness: 3½ to 4
Streak: Light yellow to white
Colour: Greenish yellow
Environments
Plutonic igneous environments
Hydrothermal environments
Tewite was approved in 2014, but to date (July 2022) it has been reported only from the type locality.
Localities
At the type locality, Nanyang, Huaping County, Lijiang, Yunnan, China, tewite occurs in
biotite–quartz
monzonite, near the contact zone with
gabbro. The associated minerals include
K-feldspar, biotite,
clinoamphibole, ilmenite,
zircon, zoisite,
tourmaline, monazite-(Ce),
allanite-(Ce), scheelite,
tellurite and wumuite. Tewite
forms platy greenish-yellow crystals that range up to 0.5 mm in size.
The formation of tewite may be related to the nearby quartz-vein-type
gold mineralisation; it is formed by the metasomatic reaction of a
high-temperature fluid rich in tungsten and
tellurium with the K-feldspar in
the monzonite
(EJM 31.1.145–152).
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