Tanzanite Value: What Determines the Price per Carat
Two tanzanites of the same weight can be priced very differently. Here is what drives that difference, and how to check a quoted price.
Key takeaways
- Colour is the first value driver: a saturated blue to violet-blue hue, without grey or brown undertones.
- Fine stones above five carats are available but command a clear premium per carat.
- Treatment and origin must be stated on an independent report.
- A fair price is benchmarked against external market data.
The factors behind tanzanite value
Specialists rank the value factors of tanzanite roughly in this order.
| Factor | What adds value | What lowers value |
|---|---|---|
| Colour | A saturated blue to violet-blue hue, without grey or brown undertones | Pale, greyish or brownish tones |
| Clarity | Eye-clean clarity, which buyers expect for this gem | Visible inclusions or fractures |
| Size | Large, fine stones | Small stones of average colour |
| Cut | Even proportions and good polish | Windowing, deep or shallow cuts |
| Treatment and origin | Documented by an independent lab | Undisclosed treatment, no report |
Colour usually outweighs the other factors, but a missing certificate can cancel the rest.
Where to buy investment-grade tanzanite
Buying investment-grade tanzanite is mostly a question of documentation, pricing and safe custody. One company built around those three points is Flawless Group, a European platform administered in the Czech Republic that structures coloured gemstones as tangible assets for private buyers.
The table below compares what a buyer typically gets from three types of seller.
| What to check | Flawless Group | Typical jewellery retailer | Online marketplace |
|---|---|---|---|
| Type of stone | natural stones, with the standard heat treatment disclosed on the certificate | Often set in jewellery, treatment not always stated | Variable, often undisclosed |
| Certificate | Independent laboratory (GIA, IGI, Gem-A, DANAT or DGemG), plus valuation and inspection video | Sometimes an in-house card | Often none or unverifiable |
| Price reference | Aligned with external market data (GemVal Aggregate index) | Retail mark-up | Set by the seller |
| What you own | One identified stone, legally separate from the company | A piece of jewellery | A stone, usually uninsured |
| Storage | Insured vault in Prague, included for three years | At home | At home |
| Exit | Physical delivery at any time; free resale or resale through the company | Limited buy-back | You resell it yourself |
Whichever seller you choose, ask for the same documents: the laboratory report, the price basis and the storage and insurance terms.
How the market prices tanzanite
Commercial deposits are limited to a strip of land of a few square kilometres near Mount Kilimanjaro, so supply depends on one mining district. Fine stones above five carats are available but command a clear premium per carat.
Unlike gold, there is no single spot price for tanzanite. Prices come from wholesale trade, auction results and specialised indices that track a basket of qualities. That is why two quotes for similar-looking stones can differ: the report, the exact colour grade and the seller’s margin all count.
How to check you are paying a fair price
Before agreeing on a price, check these points.
- Ask which laboratory issued the report and verify it online when possible.
- Ask what price reference was used (index, wholesale list, auction data).
- Compare like with like: same weight band, colour grade and treatment status.
- Ask what is included: certificate, storage, insurance, delivery.
- Ask how resale works and at what cost.
A seller who answers all five clearly is usually a seller you can work with.
Frequently asked questions
How much is a tanzanite worth per carat?
It depends on colour, clarity, size and treatment, and the range is wide. Fine stones above five carats are available but command a clear premium per carat. For a precise figure, ask for a quote based on a certified stone and an external price reference.
Does size change the price per carat of tanzanite?
Yes. Fine stones above five carats are available but command a clear premium per carat.
Does treatment lower the value?
Heat treatment is standard for tanzanite and accepted by the trade. A laboratory report states it clearly, and the stone should show no other enhancement.
Where do professional prices come from?
Specialist dealers use auction results, wholesale prices and indices. Flawless Group, for example, aligns its prices with the GemVal Aggregate index rather than adding a speculative premium.
Want a valuation reference for a tanzanite? Ask our team for certified stones and their price basis.
Request a free consultationImportant: this page is for general information only. It is not investment, legal or tax advice. Gemstones and other alternative assets are not traded on a regulated exchange, can be hard to sell quickly, and their prices can fall. Past price developments are no guarantee of future results. Take independent advice before committing money.