The Deep Blue Magic: A Collector's Guide to Tanzanite, December's Luxury Birthstone
Tanzanite: The Investment-Grade December Birthstone
Discovered in 1967 and championed by Tiffany & Co., Tanzanite is one of the most significant gemstone finds of the last century. As a December birthstone, it represents rarity, transformation, and the collectible side of the colored stone market.
1. Core Value: Irreplaceable Rarity & Investment Appeal
Tanzanite’s high value is primarily driven by its unique, non-renewable source.
- Exclusive Source: Tanzanite is mined only in the Merelani Hills of Tanzania. This extreme geographical limitation creates a degree of scarcity that few other gemstones share.
- Finite Supply: Industry experts estimate that commercial mining may last only another 15–20 years. This looming depletion is why high-quality Tanzanite increasingly appears in investment and heirloom collections.
- Main Value Driver: While size and clarity matter, Tanzanite’s value is overwhelmingly determined by color saturation. The richer the violet-blue hue, the higher the price per carat.
2. Professional Identification: Color, Pleochroism & Treatment
Understanding two key characteristics will help you evaluate genuine, high-quality Tanzanite.
A. Pleochroism (Color Change)
Tanzanite displays trichroism, meaning it can show three different colors depending on viewing angle:
- Blue
- Violet
- Red-burgundy (under some lighting conditions)
Top-grade Tanzanite has a strong shift between blue and violet.
Avoid stones that appear gray, brown, or pale — these have low saturation and low value.
B. Heating Treatment
- Industry Standard: Nearly all natural Tanzanite is heat-treated to remove natural brownish or yellow undertones and reveal desirable blue and violet colors.
- Stable & Permanent: Heating is accepted in the gemstone trade and does not harm durability.
- Important Disclosure: Truly unheated Tanzanite is extremely rare and should come with a respected laboratory certificate — beware of sellers claiming otherwise.
3. Durability, Wearability & Care Guide
Tanzanite’s hardness affects which jewelry types are most suitable.
| Assessment | Conclusion | Recommendation |
|---|---|---|
| Mohs Hardness: 6.5–7.0 | Moderately soft; easily scratched by daily materials | Handle gently |
| Impact Resistance: Brittle | Not ideal for engagement rings | Best for pendants & earrings |
| Jewelry Type | Protect from impact | Use bezel or semi-bezel settings |
Cleaning & Care
- Never: Use ultrasonic or steam cleaners — vibrations and heat can damage internal structures.
- Best Method: Warm, mild soapy water + soft cloth or soft-bristle brush.
- Avoid: Perfumes, hairspray, lotions, and household chemicals.
4. Famous Tanzanite: The Queen of Kilimanjaro
One of the most iconic Tanzanites ever discovered:
- Weight: 242 carats
- Setting: A royal tiara featuring 803 Tsavorite garnets and 913 diamonds
- Symbolism: Represents Tanzanite’s status as a luxury gemstone and modern collectible
GemGuidePro Final Verdict
Tanzanite is a gemstone of modern romance, rarity, and long-term value.
For the best December birthstone experience:
- Choose highly saturated violet-blue color
- Insist on proper disclosure of heat treatment
- Use pendants or earrings over rings to protect against impact
If you’re selecting Tanzanite as a gift or investment, a bezel or semi-bezel setting provides beautiful display with added protection for daily wear.