Composite oxide, tellurium- and tungsten- bearing mineral
Specific gravity: 6.903 calculated
Hardness: 3½ to 4
Streak: Light yellow to white
Colour: Greenish yellow
Plutonic igneous environments
Tewite was approved in 2014, but to date (July 2022) it has been reported only from the type locality.
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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