Few gemstones make an impression like sapphires do. Occurring in every colour of the rainbow, the gemstone has excellent durability and are among the strongest natural gemstones in existence, second only to diamonds. The most valuable sapphires come in a mid-blue colour with a concentrated hue that remains constant under all lighting conditions.
Mohs Scale Hardness
9.0
Specific Gravity
3.98 - 4.06
Birefringence
0.008
Refractive Index
nω=1.768 - 1.772
nε=1.760 - 1.763
