Tanzanite: From Kilimanjaro’s Depths to a Modern Investment Treasure
Discovery and Origin
Tanzanite was discovered in 1967 in the Merelani Hills, near Mount Kilimanjaro in northern Tanzania. A Maasai herder reportedly found sparkling blue crystals on the ground after a lightning strike had caused a bushfire. What was first thought to be sapphire turned out to be a new variety of the mineral zoisite.
Shortly after its discovery, Tiffany & Co. recognised the gem’s exceptional beauty and rarity. The American jeweller named it tanzanite, after its country of origin, and introduced it to the international market in 1968. From that moment, tanzanite became one of the most admired and commercially successful gemstones of the twentieth century.
A Unique Geological Miracle
Tanzanite is found only in one place on Earth — a narrow strip of land about seven kilometres long and two kilometres wide at the base of Mount Kilimanjaro. Geologists estimate that the conditions required for its formation occurred more than 500 million years ago and are unlikely to be repeated elsewhere. This geographical exclusivity makes tanzanite approximately a thousand times rarer than diamond.
The gem’s most distinctive feature is its trichroism, meaning it displays three different colours — blue, violet, and burgundy — depending on the viewing angle and the quality of the light. After heat treatment, which stabilises its deep blue-violet hue, tanzanite reveals a colour often described as richer and more complex than sapphire.
Market Value and Investment
Since its introduction, tanzanite’s value has fluctuated with supply, demand, and mining restrictions in Tanzania. Because the entire global supply comes from one area, the gemstone’s availability is inherently limited. The Tanzanian government has also implemented export controls and introduced initiatives to encourage local cutting and value addition, further tightening the flow of top-quality stones.
Prices depend heavily on colour saturation, clarity, and carat weight. Fine-quality tanzanites with a vivid royal blue or deep violet hue, can command prices comparable to medium-quality sapphires. Large stones over ten carats, particularly those free of visible inclusions, are increasingly rare and sought after by collectors and connoisseurs.
From an investment perspective, tanzanite offers both opportunity and risk. Its rarity and finite supply suggest potential for long-term appreciation, especially if the Merelani deposits become depleted within the next few decades. However, unlike diamonds or coloured sapphires, tanzanite does not yet have a fully developed secondary market, which makes liquidity lower.
Investors should focus on quality over size, choosing stones with exceptional colour and clarity, ideally accompanied by certification from reputable gemological laboratories such as GIA or IGI. The gemstone’s appeal is also tied to its story: a single-source gem with cultural and geological significance, which resonates with collectors seeking uniqueness and provenance.
Tanzanite remains one of the most captivating modern discoveries in the world of gemstones. Its vibrant blue-violet beauty, remarkable rarity, and exclusive Tanzanian origin make it a compelling choice for those who appreciate both aesthetic and investment value. While it may not yet rival the diamond market in scale or liquidity, its allure lies in its singularity — a gemstone born from the heart of Africa, destined to remain truly one of a kind.
Image Credits: HowStuffWorks
