Sapphire
Corundum in every color except red — the most versatile precious stone.
Sapphire is the non-red variety of corundum, though blue sapphire is by far the most recognized and commercially important. The stone's exceptional hardness (9 on Mohs), broad color range, and historical significance make it one of the most important gemstones in the trade. Kashmir sapphires are legendary for their velvety blue color and cornflower hue, while Sri Lankan (Ceylon) and Myanmar stones also carry strong provenance premiums. Padparadscha — a rare pink-orange variety — is among the most sought-after colored gemstones in existence.
Physical Properties
| Hardness (Mohs) | 9 |
| Refractive Index | 1.762–1.770 |
| Specific Gravity | 3.95–4.03 |
| Crystal System | Trigonal |
| Chemical Formula | Al₂O₃ (with Fe, Ti) |
Color Varieties
Major Sources
Sri Lanka · Myanmar · Kashmir (historical) · Madagascar · Australia · Montana (USA) · Thailand
Pricing Factors
Color
Vivid, medium-toned blue without grayish or greenish modifiers commands the highest prices. Kashmir 'cornflower' blue is the reference standard.
Origin
Kashmir sapphires can sell for 10x the price of equivalent stones from other origins. Sri Lankan and Burmese stones carry strong premiums.
Treatment
Heat treatment is standard and accepted. Beryllium-diffused sapphires are controversial and trade at significant discounts. Unheated stones carry 50–200%+ premiums.
Variety
Padparadscha sapphires are among the rarest and most expensive varieties. Color-change sapphires also command strong premiums.
Care Instructions
Do
- Clean with warm soapy water and a soft brush
- Ultrasonic and steam cleaning are generally safe for untreated or heat-only treated sapphires
- Excellent for daily wear due to exceptional hardness
Don't
- Don't use ultrasonic on diffusion-treated or fracture-filled stones
- Avoid sudden temperature changes
- Don't expose to harsh chemicals unnecessarily
Cleaning Method
Warm soapy water is the safest universal method. Ultrasonic and steam cleaners work well for most sapphires. Always verify the treatment before choosing a cleaning method.
Insider Buying Tips
For engagement rings, sapphire is the best colored stone option — 9 on Mohs means it handles daily wear beautifully.
Montana sapphires offer unique teal and blue-green colors at accessible price points.
Heat-treated sapphires are industry standard — don't overpay for unheated unless the lab report is from a top lab.
View sapphires in multiple lighting conditions — they can shift dramatically between daylight and incandescent light.
Consider padparadscha sapphires as a distinctive alternative to pink diamonds at a fraction of the cost.
Did You Know?
Princess Diana's engagement ring — now Kate Middleton's — features a 12-carat Ceylon blue sapphire.
The word 'sapphire' comes from the Greek 'sappheiros,' which may have originally referred to lapis lazuli.
Star sapphires display a six-rayed star pattern called asterism, caused by needle-like rutile inclusions.
Related Resources
Related Gemstones
Diamond
The hardest natural substance and the benchmark of the gemstone world.
Ruby
The king of colored gemstones, valued for its vivid red brilliance.
Spinel
The great imposter — historically mistaken for ruby and sapphire, now prized in its own right.
Tanzanite
Found in only one place on earth — a violet-blue stone rarer than diamond.