Chemistry:Tlalocite

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Tlalocite
Tlalocite-130808.jpg
Tlalocite spherules from Bambollita Mine (Oriental Mine), Moctezuma, Mun. de Moctezuma, Sonora, Mexico (picture width: 3 mm).
General
CategoryMineral
Formula
(repeating unit)
Cu10Zn6(TeO4)2(TeO3)(OH)25Cl · 25 H2O
Strunz classification7.DE.20
Dana classification33.3.2.1
Crystal systemOrthorhombic
Unknown space group
Unit cella = 16.78, b = 19.985
c = 12.069 [Å], Z = 4
Identification
ColorCapri blue, green in transmitted light
Crystal habitVelvety crusts or spheres, arced bands
FractureSectile, curved shavings or scrapings
TenacityGummy and sectile
Mohs scale hardness1
StreakPale blue
DiaphaneityTranslucent
Specific gravity4.55 (measured) 4.58 (calculated)
Optical propertiesBiaxial (-)
Birefringenceδ = 0.052
PleochroismGreen, bluish green
2V angle64
Ultraviolet fluorescencenone
SolubilityInsoluble
References[1][2][3][4]

Tlalocite is a rare and complex tellurate mineral with the formula Cu10Zn6(TeO4)2(TeO3)(OH)25Cl · 27 H2O. It has a Mohs hardness of 1, and a cyan color. It was named after Tlaloc, the Aztec god of rain, in allusion to the high amount of water contained within the crystal structure.[2][3] It is not to be confused with quetzalcoatlite, which often looks similar in color and habit.

Occurrence

Tlalocite was first identified in the Bambollite mine (La Oriental), Moctezuma, Municipio de Moctezuma, Sonora, Mexico and it was approved by the IMA in 1974. It often occurs together with tenorite, azurite, malachite and tlapallite. It is found in partially oxidized portions of tellurium-bearing hydrothermal veins.[4][5]

References