Zeer Mooie Witte Kunziet 12x10 mm Ovaal 6.45 CT. Clarity: Eye Clean Hardness: 6.5 - 7 Specific Gravity: 3.2 Refractive Index: 1.66 Chemical Composition: LiAlSi2O6, Lithium Aluminum Silicate Crystal Structure: Monoclinic Treatment: None