Tellurite

tellurite

emmonsite

tellurium

nagyagite

Images

Formula: TeO2
Simple oxide of tellurium, orthorhombic paramorph of tetragonal paratellurite
Crystal System: Orthorhombic
Specific gravity: 5.88 to 5.92 measured, 5.75 calculated
Hardness: 2
Streak: White
Colour: White to yellow, bright yellow to orange-yellow; nearly colourless in transmitted light
Solubility: Very slightly soluble in water (Mindat)
Environments

Hydrothermal environments

Tellurite is a secondary mineral resulting from the oxidation of tellurium and tellurides in the oxide zone of some hydrothermal mineral deposits. Associated minerals include tellurium, tetradymite, nagyágite and many secondary tellurates (HOM, Webmin).

Localities

At Gold Hill, Yukon Territory, Canada, tellurite occurs with native gold, sylvanite, hessite and sulphides (R&M 96.3.221).

At Moctezuma, Moctezuma Municipality, Sonora, Mexico, tellurite, an oxidation product of tellurium, ranks second to emmonsite in abundance at the Moctezuma mine. It forms radial or parallel clusters of well-formed acicular crystals, filling fractures in ore and occurring in cavities. The best specimens have beautiful, lustrous, transparent, 2.5 cm crystals of a bright orange colour and are quite spectacular. Tellurite is associated with all other tellurium minerals, but is not generally in direct contact with native tellurium. It also forms opaque, pale orange crystals and parallel clusters, commonly with flat pinacoidal terminations. Associated species include quartz, tellurium, paratellurite, spiroffite, xocolatlite and poughite(?) (Minrec 55.6.850-851).
Tellurite from Moctezuma - Image

The type locality is Faţa Băii, Zlatna, Alba, Romania.
Tellurite from Faţa Băii - Image

At the Tintic Mineral District, Utah, USA, Nicely formed, bright yellow tellurite crystals have been found at the Trixie, Centennial Eureka and North Star mines, associated with telluride minerals of which tellurite is an alteration product. The crystals range from less than 1 mm to several millimeters in size, and from transparent to opaque; most commonly they occur on a quartz matrix. A very nice phantom of an opaque tellurite crystal embedded in a transparent yellow tellurite crystal was found at the North Star mine, associated with other tellurides and sulphides (MinRec 55.2.225).
Tellurite from Tintic - Image

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