Spinel on Calcite Matrix | Natural red UV reactive crystal, mineral specimen from AfghanistanSpinel on calcite from Afghanistan are striking mineral specimens in which well formed spinel crystals sit naturally atop a contrasting white calcite matrix. Spinel is often purple pink to red, and features octahedral faces. These rare and aesthetic combinations are typically found in marble and metamorphosed carbonate rocks of regions like the Koksha Valley in Badakhshan Province, where Afghanistans rich geological history has produced world class