Saturday, March 4, 2017

Tucson Gem & Mineral Show 2017 - 3

This piece was being sold as plain calcite crystals from Chichuahua, Mexico.

The orange and red colors are caused by iron-hematite inclusions in the calcite, which inhibit fluorescence. They are also characteristic of a type of calcite called "mariposa," or "butterfly" calcite, known to respond to shortwave UV. 4.5"x2.5"

Broken faces of the crystals reveal a bright red pattern of fluorescence called "zoning."



This is most clearly visible on the sawcut bottom of the specimen.



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