Utahite

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.

Utahite
Utahite and jarosite
General
Category	Tellurate minerals
Formula (repeating unit)	Cu5Zn3(Te^6+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]

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

1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
2. Utahite, Webmineral.com
3. Utahite, Mindat.org
4. Handbook of Mineralogy