Bornite Coated Chalcopyrite Crystals With Pinkish Calcite

Guanajuato specimen: iridescent Bornite-coated Chalcopyrite crystals with pink Calcite. Sharp metallic luster, rainbow hues.

This striking mineral specimen showcases a dramatic interplay of colors and textures. 

• The primary attraction is the iridescent Bornite, which forms a vibrant blue-purple coating over well-defined Chalcopyrite crystals. 
• The Chalcopyrite appears as metallic golden patches where the Bornite coating is thinner, creating a striking contrast. 
• Translucent pink Calcite crystals add a soft yet vivid accent, completing the specimen's visual appeal.

The piece originates from Guanajuato, Mexico, a historic mining district renowned for its copper and silver deposits. The mineral association suggests formation in a hydrothermal system, where Bornite developed as a secondary mineral over primary Chalcopyrite, with late-stage Calcite crystallizing in voids. This combination of minerals is relatively uncommon, making the specimen particularly noteworthy.

Provenance adds significant value to this specimen. It was part of the Philadelphia Academy of Natural Sciences collection in the early 1940s, placing it among historically documented mineralogical material. Old-collection pieces from this era are increasingly sought after by serious collectors. The specimen remains stable, though storage in moderate humidity is recommended to preserve the Bornite's iridescence. For collectors of Mexican minerals or classic sulfide specimens, this piece represents an excellent combination of aesthetics, mineralogy, and historical significance.