Chemistry:Xocomecatlite

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Xocomecatlite
Xocomecatlite-616339.jpg
Xocomecatlite (green) in quartz matrix, collected from Trixie Mine, East Tintic District, East Tintic Mountains, Utah, United States
General
CategoryTellurate mineral
Formula
(repeating unit)
Cu3(TeO4)(OH)4
Strunz classification7.BB.50
Crystal systemOrthorhombic
Unknown space group
Unit cella = 12.14 Å, b = 14.31 Å
c = 11.66 Å; Z = 12
Identification
Formula mass450.26 g/mol
ColorGreen, emerald green
Crystal habitAggregates of radial to spherulitic or botryoidal acicular crystals
TenacityBrittle
Mohs scale hardness4
Streaklight green
DiaphaneityTranslucent
Specific gravity4.65
Density4.42 g/cm3
Optical propertiesBiaxial (−)
Refractive indexnα = 1.775 nβ = 1.900 nγ = 1.920
Birefringenceδ = 0.145
PleochroismRich bluish greens
2V angleMeasured: 41°
References[1][2][3]

Xocomecatlite is a rare tellurate mineral with formula: Cu3(TeO4)(OH)4. It is an orthorhombic mineral which occurs as aggregates or spherules of green needlelike crystals.

It was first described in 1975 for an occurrence in the Oriental mine near Moctezuma, Sonora, Mexico. It has also been reported from the Centennial Eureka mine in the Tintic District, Juab County, Utah and the Emerald mine of the Tombstone District, Cochise County, Arizona in the United States . The name is derived from xocomecatl, the Nahuatl word for "bunches of grapes", and alludes to the mineral's appearance as a set of green spherules. It occurs in the oxidized zone of gold-tellurium veins in altered rhyolite. It occurs associated with other rare tellurate minerals: parakhinite, dugganite, tlapallite, mcalpineite, leisingite, jensenite; the sulfate–phosphate minerals: hinsdalite–svanbergite; and the oxide goethite.[2][3]

References

  1. Xocomecatlite Mineral Data on Webmineral
  2. 2.0 2.1 Handbook of Mineralogy
  3. 3.0 3.1 Mindat.org
  4. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode2021MinM...85..291W.