Utahite
(repeating unit)Cu5Zn3(Te6+O4)4(OH)8·7H2O IMA symbol Uta[1] Strunz classification 7.DE.25 Crystal system Triclinic
Unknown space group Unit cell a = 8.794 Å, b = 9.996 Å
c = 5.66 Å; α = 104.1°
β = 90.066°, γ = 96.3333°; Z = 1 Identification Formula mass 1,542.46 g/mol Color Pale blue, greenish blue Crystal habit Prismatic thin tabular to bladed crystals; as sheaves and bow tielike clusters Cleavage none Fracture Brittle – uneven Mohs scale hardness 4–5 Luster Vitreous to pearly Streak Pale blue Diaphaneity Translucent Specific gravity 5.33 Optical properties Biaxial Refractive index nα = 1.830 – 1.840 nβ = 1.830 – 1.900 nγ = 1.880 – 1.900 Birefringence δ = 0.050 – 0.060 Dispersion Strong References [2][3][4]
Unknown space group
c = 5.66 Å; α = 104.1°
β = 90.066°, γ = 96.3333°; Z = 1
Utahite is an extremely rare secondary copper zinc tellurate mineral found as a product of oxidation. Its chemical formula is Cu5Zn3(Te6+O4)4(OH)8·7H2O.
It was first described in 1997 for an occurrence in the Centennial Eureka mine, one mile southeast of Eureka, Tintic District, Juab County, Utah, US (type locality). The discovery site was a mine dump of a hydrothermal ore deposit where it occurs with cesbronite and quartz.[4] It has also been reported from the Empire Mine in the Tombstone District of Cochise County, Arizona.[3]
References
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