Spinel Kristal ± 0.25 CT. 4 mm Natuurlijke Pyramide Color: Noble Red / Top Pigeon Blood Red Clarity: Clean Luster: Good Origin: Burma Hardness: 7.5 - 8.0 Specific Gravity: 3.6 - 4.0 Refractive Index: 1.71 - 1.76 Chemical Composition: MgAl2O4 , Magnesium Aluminum Oxide Crystal Structure: Isometric