Fascinating Utahite with Xocolatlite Crystals

Intense blue utahite groups on baryte with minor dagenaisite and red xocolatlite. Associated with xocolatlite is svanbergite.

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.

Fascinating Utahite with Xocolatlite Crystals
North Star Mine, Mammoth, Tintic District, Juab County, Utah, United States of America. Photo: Joy Desor Mineralanalytik

Xocolatlite is a sulfate mineral named for its chocolatey appearance. Discovered in the La Bambolla gold mine of Moctezuma, Sonora, Mexico, Xocolatlite's name is derived from the Nahuatl word xocolatl (literally "bitter water"; a root word of "chocolate"), a drink made from cocoa, water, and chili.  It has also been called Eakleite.

Xonotlite is named for its type locality, Tetela de Xonotla, Puebla, Mexico.

It frequently forms tuffs of fine white acicular crystals in veins in serpentine formations and along contact zones. 

Chemical formula is: Ca2Mn4+2(Te6+O6)2·H2O
Color is Colorless, Gray, Lemon white, Light gray, or Pink.
Transparency: Specimens are transparent.
Luster: Vitreous to silky.
Crystal System is monoclinic.
Crystal Habits include tuffs of acicular fibers and massive.
Hardness is 6.5.
Specific Gravity is approximately 2.7 (average).
Streak is white.
Notable Occurrences are Tetela de Xonotla, Puebla, Mexico, Arizona, USA, and South Africa.
Best Field Indicators are locality, color, crystal habit and hardness.

Next Post Previous Post