Tanzanite – The Rare Blue-Violet Gem | Origins & Value | GemMine
What Is Tanzanite?
Tanzanite is one of the rarest gemstones on Earth, found in only one location in the world: a small area of approximately 7 square kilometres at the foot of Mount Kilimanjaro in northern Tanzania. It is a blue-violet variety of the mineral zoisite, coloured by vanadium, and is renowned for its exceptional trichroism — appearing different colours (blue, violet, and burgundy/red) when viewed from different angles. Tanzanite scores 6–7 on the Mohs hardness scale.
Where Does Tanzanite Come From?
Tanzanite is found exclusively in the Merelani Hills of the Manyara Region in northern Tanzania. This single source makes it approximately 1,000 times rarer than diamonds. The deposit was discovered in 1967 by Masai tribesman Ali Juuyawatu and subsequently commercialised by Tiffany & Co., who named the stone after its country of origin. The mines are divided into four blocks (A, B, C, D), with Block C traditionally producing the highest quality material.
Tanzanite Colours
- Deep Blue-Violet – The most valuable colour, exhibiting a rich, saturated blue with violet undertones, especially in larger stones (3ct+).
- Violet-Blue – Stones with more violet than blue; equally beautiful.
- Bluish-Violet – Commercial quality with less colour depth.
- Lavender – Pale lilac tone from lighter-coloured rough; more affordable.
The colour of tanzanite is graded on a proprietary scale by the Tanzanite Foundation (TZF), ranging from 1V (lightest violet) to 6B (deepest blue).
Ethical Mining
Tanzanite mining is controlled by the Tanzanian government, which mandates that only Tanzanian citizens may hold mining licences. The Tanzania Mineral Audit Agency (TMAA) and Tanzanite Foundation's TanzaniteOne Trading promote responsible supply chains. GemMine sources tanzanite through certified channels adhering to the Tanzanite Code of Practice.
Tanzanite Rarity & Investment
Tanzanite is a finite resource. Geological surveys suggest the current deposits could be exhausted within the next 20–30 years. With a single mine site and growing demand from Asia and the West, tanzanite is increasingly viewed as an investment gemstone. Since its discovery in 1967, prices have risen dramatically, and as supply tightens further, investment-grade tanzanite (large, deeply saturated stones with certificates) is expected to appreciate significantly.
Tanzanite Price Appreciation (GBP)
| Year | Avg. Price per Carat (GBP) - 3ct D Block AAA | Change |
|---|---|---|
| 2015 | £280 | – |
| 2018 | £380 | +35.7% |
| 2020 | £460 | +21% |
| 2022 | £620 | +34.8% |
| 2024 | £850 | +37% |
| 2026 (est.) | £1,100+ | +29% |
Famous Tanzanites
- The Mawenzi Tanzanite – One of the largest faceted tanzanites, weighing over 3,300 carats in rough form.
- Queen of Kilimanjaro – A 242-carat tanzanite set in a brooch with diamonds and tsavorite garnets, exhibited in the Royal Ontario Museum.
Why Invest in Tanzanite?
Tanzanite is unique among gemstones in having a guaranteed, countdown-to-depletion supply dynamic. With the world's only deposit in northern Tanzania showing declining ore grades and increasing mining depths, supply will only reduce. Combined with growing global demand, tanzanite represents a compelling long-term investment for collectors and investors alike. GemMine offers certified tanzanite graded by the Tanzanite Foundation.