Sodaliet ± 0.50 CT. 5 mm Ronde Cabochon Color: Mottled Navy Blue Clarity: Opaque Luster: Good Origin: Canada Hardness: 5.5 - 6.0 Specific Gravity: 2.1 - 2.3 Refractive Index: N/A Chemical Composition: Na4Al3(SiO4)3Cl, Sodium Aluminum Silicate Chloride Crystal Structure: Isometric Treatment: None