A History of Tanzanite, December’s Newest Birthstone

Discovered in 1967, tanzanite is one of the newest members of the birthstone family. Its lively blue and violet hues have captivated jewelry designers of the late 20th and early 21st centuries. But this gemstone is said to be a “generational” stone – what does that mean, and why?

The first tanzanite crystal was said to be found by a Maasai tribesman, thought to be Ali Juuyawatu, near the Mererani Hills in Tanzania, the southern foothills of Mount Kilimanjaro. Manuel d’Souza, a local treasure hunter, was alerted to the presence of the stone and, thinking he’d found a new deposit of sapphires, registered several mining claims in the area. The mysterious new gemstone was first correctly identified as zoisite by a geologist for the Tanzanian government.

Hearing of the vibrant new gem, Tiffany & Co. invested in the blue zoisite, dubbing it “tanzanite” after its home country and becoming its primary distributor. The company proudly advertised that tanzanite could only be found “in Tanzania and Tiffany’s“. With its sparkling blue color, tanzanite quickly rose to popularity among designers and consumers alike. In 2002, the American Gem Trade Association dubbed tanzanite a birthstone for December in its first update to the birthstone list since 1912, finalizing its place among historically valued gems like sapphires and emeralds.

These days, many sellers of tanzanite will promote it as an investment stone, explaining that as the only tanzanite mine in the world goes dry, the gem’s prices will skyrocket. But is the world really running out of tanzanite? Geologists estimate the commercial tanzanite mines will be exhausted of the material in 15 to 25 years, making the time from its discovery to its depletion roughly a single human lifespan, thus, a “generational” gemstone. However, in April of 2018, the President of Tanzania, John Magufuli, revealed a new tanzanite source had been discovered, but its location is still under wraps. Additionally, zoisite, the mineral species to which tanzanite belongs, is relatively common worldwide. An entrepreneurial miner need only discover a source of zoisite containing the correct elements to allow it to be heated to a blue color to completely flood the tanzanite market.

Do you think tanzanite will continue to be found after the current mines have run out? The future of this precious gemstone is still up in the air – or rather, down in the earth!