Tourmaline
The rainbow gem — no other mineral occurs in as many colors.
Tourmaline is a boron silicate mineral group that occurs in virtually every color of the spectrum. Its extraordinary color range — from neon blue Paraíba to vivid pink rubellite to chrome green — makes it one of the most diverse and collectible gem families. Paraíba tourmaline, discovered in 1989 in Brazil, is among the most expensive gemstones per carat due to its electric neon blue-green color caused by copper. Tourmaline is also notable for its piezoelectric and pyroelectric properties — it generates an electric charge when heated or compressed.
Physical Properties
| Hardness (Mohs) | 7–7.5 |
| Refractive Index | 1.624–1.644 |
| Specific Gravity | 3.02–3.26 |
| Crystal System | Trigonal |
| Chemical Formula | Complex borosilicate (variable) |
Color Varieties
Major Sources
Brazil · Mozambique · Nigeria · Afghanistan · Madagascar · USA (California, Maine) · Sri Lanka
Pricing Factors
Variety
Paraíba tourmaline is the most expensive — top stones exceed $50,000/carat. Chrome tourmaline and fine rubellite are also premium. Standard green and pink are more accessible.
Color Saturation
Vivid, saturated colors without dark or muddy tones command the highest prices within each variety.
Copper Content (Paraíba)
For Paraíba tourmaline, copper-bearing status must be confirmed by a gemological lab. The neon glow is the key indicator.
Clarity
Type II gem — some inclusions are expected. Eye-clean stones command premiums, but rubellite is commonly included.
Care Instructions
Do
- Clean with warm soapy water and a soft brush
- Safe for everyday wear in most jewelry types
- Store separately to prevent scratching softer stones
Don't
- Avoid ultrasonic cleaners for included stones
- Don't expose to extreme heat
- Avoid steam cleaning
Cleaning Method
Warm soapy water is the safest method. Ultrasonic is acceptable for clean stones but avoid it for heavily included material.
Insider Buying Tips
Chrome tourmaline is the most undervalued green gemstone on the market — vivid color, no treatment, excellent value.
Be extremely careful with 'Paraíba' claims — demand a lab report confirming copper content from GIA, Gübelin, or GRS.
Watermelon tourmaline makes unique conversation-piece jewelry — best displayed in slice form.
For rubellite, accept some inclusions — eye-clean rubellite is rare and commands high premiums.
Afghan and Nigerian tourmaline offer excellent quality at lower prices than Brazilian material.
Did You Know?
Tourmaline was the first mineral to be recognized as having pyroelectric properties — the Dutch used it to pull ash from pipes.
Paraíba tourmaline was discovered by Heitor Dimas Barbosa, who spent years digging tunnels in the Brazilian hills based on a hunch.
A Chinese Empress used tourmaline as a pillow rest, believing it promoted good health.
Related Resources
Related Gemstones
Emerald
The green jewel of royalty, prized for its saturated color above all else.
Garnet
A family of gems spanning every color — not just the deep reds.
Sapphire
Corundum in every color except red — the most versatile precious stone.
Spinel
The great imposter — historically mistaken for ruby and sapphire, now prized in its own right.