Tanzanite
Found in only one place on earth, a violet-blue stone rarer than diamond.
Tanzanite is the blue-violet variety of the mineral zoisite, discovered in 1967 near Mount Kilimanjaro in Tanzania. It is found in a single deposit roughly 4 km wide, making it approximately 1,000 times rarer than diamond by geological occurrence. Tiffany & Co. named the stone and introduced it to the market in 1968. Tanzanite is strongly trichroic, showing different colors (blue, violet, and burgundy) depending on the crystal axis and viewing angle. Nearly all tanzanite on the market has been heat-treated to shift its color from brownish to the prized blue-violet.
What are the properties of tanzanite?
| Hardness (Mohs) | 6–6.5 |
| Refractive Index | 1.691–1.700 |
| Specific Gravity | 3.35 |
| Crystal System | Orthorhombic |
| Chemical Formula | Ca₂Al₃(SiO₄)(Si₂O₇)O(OH) |
Color Varieties
Major Sources
Tanzania (sole source)
What affects tanzanite price?
Color Saturation
Deep, vivid violet-blue stones command the highest prices. Lighter 'lavender' tanzanites are more affordable. The most prized shade shows a balance of blue and violet.
Size
Prices escalate significantly above 5 carats. Fine-quality stones above 10 carats are genuinely rare and carry exponential premiums.
Clarity
Tanzanite is a Type I gem. Eye-clean clarity is expected. Visible inclusions significantly lower value.
Market Supply
As a single-source gem, tanzanite supply is finite. Mining disruptions and export regulations from Tanzania directly impact global pricing.
How much does tanzanite cost per carat?
Retail prices as of mid-2026. Actual cost depends on color, clarity, origin, and treatment.
| Quality | Price/ct | Notes |
|---|---|---|
| Pale lavender (under 2ct) | $50–$150/ct | Light saturation, common commercial grade |
| Medium blue-violet (1–3ct) | $150–$400/ct | Good color, eye-clean, heat-treated |
| Saturated violet-blue (2–5ct) | $400–$800/ct | Deep color, strong trichroism |
| Fine 3–5ct saturated | $800–$1,500/ct | Top commercial quality, GIA or equivalent cert |
| Exceptional 5ct+ top tier | $1,500–$3,000+/ct | Large, vivid stones, genuinely rare above 10ct |
How to care for tanzanite
Do
- Clean with lukewarm soapy water and a soft cloth
- Store in a padded box away from harder stones
- Best suited for earrings, pendants, and occasional-wear rings
Don't
- Never use ultrasonic or steam cleaners
- Don't wear in rings for daily use. Tanzanite is too soft
- Avoid sudden temperature changes (thermal shock can cause fractures)
Cleaning Method
Lukewarm soapy water only. Tanzanite is sensitive to heat, pressure, and sudden temperature changes. Handle with care.
How to buy tanzanite
Tanzanite is best for earrings and pendants. It's too soft for an everyday engagement ring.
Heat treatment is universal and accepted. There's no market premium for 'natural color' tanzanite.
Buy the deepest saturation you can afford. Pale tanzanite looks generic, but saturated stones are genuinely stunning.
Consider tanzanite as an investment play. The single-source supply is finite and mine production is declining.
Verify that the stone has not been coated (a treatment that wears off). Ask for a gemological report.
Did You Know?
Tanzanite was formed 585 million years ago during massive tectonic plate activity.
Geologists estimate the mines could be depleted within 20–30 years at current extraction rates.
Tiffany & Co. named the stone 'tanzanite' because they felt its scientific name (blue zoisite) was unmarketable.
Frequently asked questions
How much is tanzanite worth?
Tanzanite sells for $50 to $3,000+ per carat at retail in mid-2026. A 2 carat medium blue-violet stone runs $300 to $800 total. Saturated 5 carat+ gems with deep violet-blue color can reach $4,000 to $15,000+ for the whole stone.
Is tanzanite rarer than diamond?
Yes, by geological occurrence. Tanzanite comes from a single deposit near Mount Kilimanjaro covering roughly 4 km. Geologists estimate it is about 1,000 times rarer than diamond in the earth. Rarity in the ground does not always translate to higher retail prices, though.
Why is tanzanite so expensive?
Tanzanite costs more than many semi-precious stones because it has a single source, finite supply, and strong color demand. Mining disruptions in Tanzania, export regulations, and declining production all push prices up. Fine saturated stones above 5 carats are genuinely scarce.
Is tanzanite a good investment?
Tanzanite is a speculative buy, not a sure investment. The single-source supply is finite and prices have risen over the past two decades, but there is no liquid resale market like diamonds have. Buy tanzanite because you love the color, not because you expect to profit.
Related Resources
Related Gemstones
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Sapphire
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Spinel
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Tourmaline
The rainbow gem. No other mineral occurs in as many colors.
Comparisons
Last updated: 2026-08-12