Sturmanite, Ettringite, Charlesite (South Africa) | sturmanite crystal, mineral specimen, rare mineralsA yellow brown crystal that exhibits all three members of the solid solution series of sturmanite, ettringite and charlesite from the famous Nchwaning II Mine. This specimen has sturmanite and charlesite on the outside and ettringite on the inside of the crystal. The backlit photos highlight the translucency and yellow cored interior composed of the lemon yellow ettringite. Ex. Rob Smith Collection Size: 2. 3 x 1. 2 1. 0 Cm Weight: 3. 3G (Conversion: