Tanzanite
Tanzanite is the blue to violet variety of the mineral zoisite, and it is found in commercial quantity in one small area of northern Tanzania at the foot of Kilimanjaro. It is strongly trichroic, showing blue, violet and a brownish or burgundy third colour depending on the direction it is viewed through, and almost all of the material is heated to remove the brown and leave the blue and violet the market buys. It has been one of the most commercially successful new gemstones of the modern era and is used across fine and commercial jewellery, in large statement stones, and in collector specimens.
Listed tanzanite markets
Each line is a grade at a delivery point. Open one for its full specification and terms.
Grades
Tanzanite is bought on colour and size, and on the understanding that the material is heated. The species, the colour description including the direction the colour is read in, and the size are the terms the price is agreed against.
Species, variety and identification
8 grades
| Grade | Definition |
|---|---|
| SpeciesZoisite, confirmed by gemmological testing | Confirmed against the constants of the species. Tanzanite is the trade name for gem quality blue to violet zoisite. |
| VarietyTanzanite | Blue to violet zoisite. The name is a trade name for the variety and its use in an invoice is governed by the nomenclature standard. |
| Colouring elementVanadium | Vanadium gives the blue and violet. The brown component removed by heating is the third pleochroic colour. |
| Refractive indexReported, with the birefringence | Measured on a refractometer, separating tanzanite from sapphire, iolite and the blue simulants. |
| Specific gravityReported | Measured hydrostatically, confirming the species. |
| HardnessReported on the Mohs scale | Moderate, with perfect cleavage in one direction, which governs how the stone is cut, set and worn. |
| PleochroismDeclared, as the three observed colours | Tanzanite is trichroic. Blue, violet and the third colour appear along the three optical directions, and which one the table faces decides the finished stone. |
| Cleavage and toughnessDescribed | One perfect cleavage direction and sensitivity to thermal shock and ultrasonic cleaning, which are stated as handling and setting instructions. |
Colour
6 grades
| Grade | Definition |
|---|---|
| HueDescribed, as blue, violetish blue, bluish violet or violet | The dominant commercial dimension. Pure blue with a violet secondary is the most sought face up appearance. |
| ToneDescribed, from light to dark | Medium to medium dark tone holds the saturation. Small stones tend to read lighter, which is why size and colour are linked in this species. |
| SaturationDescribed, from weak to vivid | The dominant value term. |
| Pleochroic orientationDeclared, as the direction the table is cut to | Whether the stone is oriented to face up blue or to face up violet. It changes the appearance, the weight retention and the price. |
| Colour zoningDescribed | Zoning through the crystal, which decides orientation and yield. |
| Lighting conditionDeclared | Assessed under daylight equivalent lighting, with the incandescent appearance noted, because tanzanite reads more violet under warm light. |
Clarity and inclusions
5 grades
| Grade | Definition |
|---|---|
| Clarity typeType one, under the standard clarity classification | Tanzanite is expected to be eye clean, so visible inclusions carry a real discount. |
| Inclusion suiteDescribed | Graphite and other crystals, fingerprints and growth features. |
| Eye clean assessmentDeclared, at the stated viewing distance | The working commercial threshold in a type one species. |
| Fractures and cleavageDescribed, by position and reach | The perfect cleavage direction makes surface reaching breaks a durability term as much as a clarity term. |
| TransparencyDescribed, from transparent to translucent | Faceting and cabochon material are separate products. |
Rough form, size and yield
6 grades
| Grade | Definition |
|---|---|
| Rough weightCarats, per piece and per parcel | Weighed on a calibrated balance. |
| DimensionsMillimetres, length by width by depth | Measured on the crystal or preform. |
| Estimated yieldPercentage of rough weight, declared as an assessment | An opinion rather than a warranty. Orientation for colour costs weight, and the assessment states which orientation it assumes. |
| Shape and formDeclared, as crystal, cobbed piece or preform | Prismatic crystals and cobbed fragments from the block workings. |
| OrientationDeclared | Which pleochroic direction the table faces, which is the single most consequential cutting decision in this species. |
| Size distributionDeclared, as the count within each stated weight band | For a sorted parcel, the distribution across sizes. Colour strengthens with size, so the distribution carries the parcel price. |
Treatment and disclosure
6 grades
| Grade | Definition |
|---|---|
| Heat treatmentDisclosed, as heated or unheated | Almost all tanzanite is heated at moderate temperature to remove the brown pleochroic colour. It is permanent, accepted and assumed unless stated otherwise, and the disclosure is still made in writing. |
| Coating and surface treatmentDisclosed | Any applied layer used to deepen the apparent colour, with its coverage and durability, because coated material has appeared in the market and is not durable. |
| Fracture fillingDisclosed, with the filler identified | Any oil, resin or glass in a surface reaching break, with the extent stated. |
| Assembled stone screeningDeclared | Confirmation that the stone is not a doublet or a composite. |
| Synthetic and imitation screeningDeclared, against the named laboratory method | Separation from synthetic forsterite, coated glass, cubic zirconia and the other blue simulants sold under the name. |
| Disclosure recordDocument, per stone or per parcel | The written treatment disclosure on the invoice and with the parcel. |
Parcel, documentation and settlement
9 grades
| Grade | Definition |
|---|---|
| Parcel compositionDeclared, by piece count and total carat weight | What is actually in the lot. A rough parcel is sold as a parcel, so the count, the weight and the size distribution are the contract. |
| Weight basisCarats, to the stated decimal place | Weighed on a calibrated balance, with the weighing certificate and the tolerance named. |
| Sealing and markingDeclared | Parcels sealed in the presence of both parties or their agents, numbered and photographed, so the goods that arrive are the goods that were inspected. |
| Laboratory reportDocument, per stone or per parcel | Issued by a named laboratory operating to the international testing competence standard, covering species, treatment and, where commissioned, origin. |
| Origin determinationDeclared, where commissioned | A laboratory origin opinion is an opinion based on inclusion suites and trace element chemistry. It is stated as such and never as a guarantee. |
| Export and import documentationDeclared | Export permit or certificate from the producing country, customs classification under the harmonized system, and any royalty or clearance certificate the origin requires. |
| Responsible sourcingDeclared | Mine or source, chain of custody, and the due diligence statement, including artisanal and small scale mining status where it applies. |
| Viewing and rejectionDeclared | Where and when the buyer may view, the memo or consignment terms if any, and the window and grounds for rejection after the laboratory report. |
| Insurance and carriageDeclared | Valuation for transit, the specialist carrier or secure courier named, and the point at which risk passes. |
Grades outside this list trade on request. Send us the contract specification you work to and we will price against it.
Locations
| Country | Region | We trade it as |
|---|---|---|
| Tanzania | East Africa | Origin and destination |
| Kenya | East Africa | Origin and destination |
| India | South Asia | Cutting and trading centre |
| Thailand | Southeast Asia | Cutting, treatment and trading centre |
| Sri Lanka | South Asia | Origin and destination |
| China | East Asia | Cutting centre and destination |
| Hong Kong | East Asia | Trading centre |
| Israel | Middle East | Cutting and trading centre |
| United Arab Emirates | Middle East | Trading hub and free zone |
| Switzerland | Europe | Trading, laboratory and vaulting centre |
| Belgium | Europe | Trading centre |
| Germany | Europe | Cutting centre and destination |
| United Kingdom | Europe | Trading centre and destination |
| France | Europe | Destination |
| Italy | Europe | Destination |
| Spain | Europe | Destination |
| United States | North America | Origin and destination |
| Canada | North America | Origin and destination |
| Singapore | Southeast Asia | Trading and finance |
| Japan | East Asia | Destination |
| Republic of Korea | East Asia | Destination |
| Australia | Oceania | Origin and destination |
| Turkey | Western Asia | Origin and destination |
| South Africa | Southern Africa | Origin and destination |
| Netherlands | Europe | Destination |
| Saudi Arabia | Middle East | Destination |
| New Zealand | Oceania | Destination |
| Brazil | South America | Origin and destination |
Origins and destinations outside this list trade on request. We are not limited to the locations shown here.
Timing
Production is when the stone comes out of the ground at origin, which follows the mining season, the water level at an alluvial working and the rhythm of artisanal digging rather than a crop calendar. Arrival is when material from that origin typically reaches a cutting or trading centre. The gap between them is sorting, export clearance and the journey to the market.
HarvestArrival
| Origin | J | F | M | A | M | J | J | A | S | O | N | D | Window |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tanzania | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest Jan to Dec, arrival Jan to DecThe Merelani hills in the Manyara region, the only commercial source of the stone in the world. Mined year round from blocked and licensed workings, with export documentation and the local certification regime established before any commitment. |
| Kenya | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest Jan to Dec, arrival Jan to DecA trading and transit point for East African coloured stones rather than a source of tanzanite. |
| India | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest Jan to Dec, arrival Jan to DecThe principal cutting centre for the species, taking rough from origin and shipping finished goods year round. |
| Thailand | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest and arrival | Harvest Jan to Dec, arrival Jan to DecHeating, cutting and trading centre, shipping year round. |
Windows outside this pattern trade on request, including forward commitments against a mine run, parcels already sitting in a cutting centre, and material held in a free trade zone or bonded vault.
Customs, packing and contract terms
Indicative terms for tanzanite. Tariff classification is the importer’s responsibility and limits change, so confirm both against the destination customs authority and the current regulation before you fix a contract.
- HS heading7103.10 Precious and semi-precious stones, unworked or simply sawn or roughly shaped
7103.99 Semi-precious stones, otherwise worked - PackingSealed and numbered parcels under a valuation certificate. Never containerised.
- Container loadingNot containerised. Moves by insured secure courier or hand carry against a declared valuation, with customs presentation at both ends.
- Contract and arbitrationCIBJO Blue Book nomenclature, with a GIA, Gubelin or SSEF report where the value warrants it. Sale on viewed and approved parcel terms with weight and treatment disclosure. Arbitration under the rules of the World Federation of Diamond Bourses or the ICC.
- Destination limitsOrigin declaration and OECD due diligence for minerals from conflict affected and high risk areas, US OFAC sanctions on Burmese ruby and jade under the JADE Act, anti money laundering registration and reporting for dealers in precious stones, and full disclosure of heat, diffusion, fracture filling and any other treatment.
Common questions
What grades of tanzanite does SIP Global trade?
We quote 40 published grades of tanzanite, including Species - Zoisite, confirmed by gemmological testing, Variety - Tanzanite, Colouring element - Vanadium, Refractive index - Reported, with the birefringence, Specific gravity - Reported and Hardness - Reported on the Mohs scale. Every grade is tied to a delivery point and a settlement route. Grades outside the published list are priced on request.
How is tanzanite graded?
Tanzanite is bought on colour and size, and on the understanding that the material is heated. The species, the colour description including the direction the colour is read in, and the size are the terms the price is agreed against. Grading runs on 6 systems: Species, variety and identification, Colour, Clarity and inclusions, Rough form, size and yield, Treatment and disclosure and Parcel, documentation and settlement.
Where does SIP Global trade tanzanite?
We trade tanzanite in Tanzania, Kenya, India, Thailand, Sri Lanka, China, Hong Kong and Israel and 20 further markets. Origins and destinations outside this list trade on request. We are not limited to the locations shown.
When is tanzanite harvested and when does it arrive?
Typical windows are Tanzania: harvest jan to dec, arrival jan to dec; Kenya: harvest jan to dec, arrival jan to dec; India: harvest jan to dec, arrival jan to dec; Thailand: harvest jan to dec, arrival jan to dec. Harvest is when the lot is taken at origin, arrival is when a shipment from that origin lands in a consuming market. Windows outside this pattern, including carry, trade on request.
What is the HS code for tanzanite?
Tanzanite is normally classified under HS 7103.10 (precious and semi-precious stones, unworked or simply sawn or roughly shaped) and HS 7103.99 (semi-precious stones, otherwise worked). The heading follows the form the goods are in at the border, and national tariffs extend it beyond six digits, so confirm the full line with the destination customs authority before you fix a contract.
How do I get a price for tanzanite?
Send the grade, the origin and the delivery window to the SIP Global desk. That is enough for a trader to come back with a level and a settlement route. 1 listed tanzanite market is published on this page, each with its full specification and terms. We take both sides, physical and financial, prompt to long dated.
Standards and data sources
The grading language on this sheet follows published standards. Trade volumes and tariff lines are public record. Verify anything here against the source.
- UN ComtradeOfficial international trade statistics by HS code
- ITC Trade MapBilateral trade flows and tariff data
- FAOSTATFAO production and trade series for agricultural commodities
Price this with our desk
Grade, origin and window if you have them. If what you are carrying does not fit the sheet above, describe it in your own words and a trader will take it from there.