Fluorite and Quartz After Calcite

Vibrant purple fluorite crystals contrasted by snowy white quartz epimorphs after scalenohedral calcite from Second Chance Mine in Tombstone, Arizona. An intriguing piece showcasing intricate multi-stage mineralization.

Some specimens, such as this one, feature a type of pseudomorph known as an epimorph, seen here as quartz after calcite. In an epimorph, one mineral forms as a coating along the surfaces of another, and the original mineral later dissolves, leaving a cast of its shape behind. This replacement and dissolution occurred in heavily fractured limestones, where hydrothermal fluids moved through the rock, depositing quartz on calcite while dissolving the calcite itself. The process points to an acidic environment, since quartz forms under the same conditions that dissolve calcite.