Utahite

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Utahite
General
Category Tellurate minerals
Formula
(repeating unit)
Cu5Zn3(Te6+O4)4(OH)8•7H2O
Strunz classification 07.DE.25
Crystal symmetry Triclinic 1 or 1
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
Color Pale blue, greenish blue
Crystal habit Prismatic thin tabular to bladed crystals; as sheaves and bow tielike clusters
Crystal system Triclinic
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 [1][2][3]

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, USA (type locality). The discovery site was a mine dump of a hydrothermal ore deposit where it occurs with cesbronite and quartz.[3] It has also been reported from the Empire Mine in the Tombstone District of Cochise County, Arizona.[2]

References[edit]

  1. ^ Utahite, Webmineral.com
  2. ^ a b Utahite, Mindat.org
  3. ^ a b Handbook of Mineralogy