Zonnensteen ±0.15 CT. 5.5x3 mm Marquise Color: White Clarity: Fine Crystal Luster: Outstanding Origin: Oregon, U.S.A. Hardness: 6 - 6.5 Specific Gravity: 2.64 - 2.68 Refractive Index: 1.533 - 1.552 Chemical Composition: NaCa(Al, Si)AlSi2O8, Sodium Calcium Aluminum Silicate Crystal Structure: Triclinic Treatment: None