SILVER ON CALCITE

ABOUT THE SPECIMEN From newer finds in the Bouismas silver mine, we have this vertical growth of milky white calcite adorned with well-crystallized native silver. The contrast and growth is gorgeous, and its sculptural appearance certainly gives it nice display value. The calcite glows red in almost any UV wavelength.   VIDEO   MORE INFO Bouismas is one of the easternmost workings in the Bou Azzer district, a Neoproterozoic five-element vein-type deposit in which Co-Ni arsenides, native silver, and bismuth mineralized in fractures cutting serpentinized Precambrian peridotite - the world's only major cobalt district where the metal is mined as a primary commodity rather than a byproduct. Silver at Bouismas occurs in a distinct sulfide-sulfosalt stage overprinting the earlier arsenide mineralization, with Mindat documenting a silver-rich vein worked from mid-2008 through spring 2010 that also produced partial pseudomorphs of allargentum and minor dyscrasite. Native silver from this window formed as arborescent and dendritic growths on white calcite matrix; a subset shows cubic and spinel-twinned crystals of unusual sharpness for the species. Most specimens arrived encased in calcite requiring careful mechanical preparation to expose the silver within. Proustite occurs as a notable associate on some matrix pieces, adding red sulfosalt contrast against the calcite. The documented production window was narrow and the vein is now exhausted, meaning all available material is fixed to what was recovered during those roughly two years of activity - a tight supply that has kept Bouismas silver consistently underrepresented in Western collections relative to its quality.