Definition
What is Blue Sapphire?
Blue sapphire is blue gem-quality corundum. The broader name sapphire also applies to corundum in many colors other than ruby red. Color, treatment status, clarity, cut, origin context, and documentation all influence market evaluation.
At a glance
Gemological properties
Values marked pending have not yet cleared the editorial source review.
| Gemstone name | Blue Sapphire | Mineral species | Corundum |
|---|---|---|---|
| Chemical formula | Al₂O₃ | Crystal system | Trigonal |
| Mohs hardness | 9 | Specific gravity | 4 |
| Refractive index | 1.762–1.77 | Birefringence | 0.008–0.01 |
| Primary color | Blue | Optical character | Pending verification |
| Luster | Pending verification | Transparency | Pending verification |
Science & context
A layered reference
What is Blue Sapphire?
Blue sapphire is blue gem-quality corundum. The broader name sapphire also applies to corundum in many colors other than ruby red. Color, treatment status, clarity, cut, origin context, and documentation all influence market evaluation.
Evidence
References & further reading
- [1]Sapphire Gemstone Overview
Gemological Institute of America
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