... . 2,high quality 3,best sevice High purity alumina (aluminum oxide), purity, 99.999% Product discriptions ModelVK-L100GCrystalaappearancewhite loose powderAverage particle size ... crystalline wafers 2, laser crystal (YAG) and artificial gem. 3, colored gemstones 4, sapphire panel High purity alumina (aluminum oxide), purity, 99.999%