- Color: any color
- Hardness: 9
- Refractive index: 1.76 - 1.78
- Density: 3.99 - 4.00
- Chemical composition: Al2O3
- Crystal structure: hexagonal
- Origins: Burma, Sri Lanka, India, Madagascar, Kenya, Tanzania, Thailand, Cambodia, China, Australia, USA.
Sapphires are a variety of corundum, existing in almost all colors. A sapphire's color is the main factor for price estimation. Heat treatment is usually applied to improve their color and reduce small inclusions. It can be difficult to exactly identify the color online, therefore we recommend that you refer to Gemval.com for an appraisal. Please accept that a value-approximation error in the 15-20% range is possible.