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Formula: MgCu2+4Zn2Te6+3O14(OH)4.6H2O
Hydrated tellurate
Crystal System: Triclinic
Specific gravity: 5.33 calculated
Hardness: 4 to 5
Streak: Pale blue
Colour: Light blue, blue-green
Luminescence: Nonfluorescent under both long wave and short wave UV
Solubility:
Environments
Localities
The type locality, the Centennial Eureka Mine, Eureka, Tintic Mining District, Juab County, Utah, ceased mining
operations in 1927, and the immense dumps of the mine were largely removed and reprocessed in 1991. At that time, a
wide variety of mineralised specimens was exposed, including several boulders which contain new
copper- and tellurium-
bearing assemblages. Utahite was observed in two of these boulders and it is extremely rare. On the holotype
material, utahite occurs both as isolated clusters to 0.6 mm of tightly bound parallel to subparallel
aggregates of numerous single crystals, and as numerous 0.2 mm isolated and grouped sheaves in small vugs of crumbly,
drusy white to colourless and dark brown quartz. Associated minerals are
leaf-green crystals of cesbronite in spherules and botryoidal crusts, and
an undefined copper-, zinc-
tellurium- bearing pale green botryoidal crust. Additional
copper- and tellurium-
bearing secondary minerals that have been identified on
similar specimens include mcalpineite,
frankhawthorneite,
jensenite, leisingite,
xocomecatlite, dugganite
and quetzalcoatlite. Utahite is a
secondary mineral that formed from the breakdown of
primary copper-,
zinc- and tellurium- bearing
sulphides
(MinRec 28: 175-179).
Utahite also has been found at the North Star and Gold Chain mines in the Tintic District
(MinRec 55.2.226-228).
Utahite from the Centennial Eureka Mine -
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