Sanidine is the high-temperature potassium feldspar of young volcanic rocks, faceting into smoky champagne and straw-gold gems of glassy clarity — an uncommon species that rewards feldspar collectors. Germany’s Eifel and Madagascar are notable sources; hardness 6.Our sanidines are natural, certified by GEMIC Institute’s gemologists and filmed for their listings. One-of-a-kind stones; worldwide tracked shipping, 30-day inspection period.