History of Tanzanite

Tanzanite is a rare variety of blue-purple Zoisite.  It was discovered and popularized in the 20th century.  As a result, it was not included in any older lapidaries, texts that describe gemstones and their powers, but it is included in many modern ones.  While blue-purple Zoisite has been found in several locations, most of the precious gemstones are from the Mererani Hills deposit in northern Tanzania.

Tanzanite was discovered in January 1967, shortly after a large bush fire had swept across the plains below Mount Kilimanjaro.  The fire burned away the grass, leaving the ground exposed, and gave a natural “heat treatment” to the reddish-brown and clear Zoisites in the area, turning them a stunning blue-purple.  Shortly after the burn, Jumanne Ngomaa a Masaii tribesman and amateur prospector crossed the Mererani Hills and saw the gems glittering in the sunlight.  He didn’t recognize them and so he took the gems to Nairobi, a city with a strong gemstone and mineral industry for formal identification.

The gems were shown to geologists and wholesale gemstone-dealer, John Saul, who quickly determined that they weren’t Sapphires, Iolites, or any other well-known blue gemstone. He sent a few samples to his father, Hyman Saul, the vice-president of Saks 5th Avenue in New York City.  Hyman Saul took the mystery stones to the Gemological Institute of America who soon identified them as blue-purple Zoisite.  The color was so remarkable that news of the find very quickly reached the ears of  Henry B. Platt, one of the leaders of the New York based jewelry company, Tiffany and Co.


Ndugu Jumanne Ngoma


Tiffany and Co advertisement for Tanzanite rings (2012)

Henry B. Platt instantly fell in love with the new gemstone, but thought that the name “blue Zoisite” wasn’t very marketable.  He feared that the word Zoisite sounded too similar to “Suicide”! So he re-branded the gems as Tanzanite and revealed it in October 1968.  The marketing campaigns focused on the rarity of the stone, with early advertisements saying that Tanzanite could only be found in two locations “Tanzania and Tiffanys!”.  The gem has been aggressively marketed by Tiffany and Co ever since, even going so far as to call it the “Gemstone of the (20th) Century”.

In 1971, the government of Tanzania nationalized the mine at Mererani Hills.  Today, this mine remains the only source for gem-quality Blue Zoisite in Tanzania.   It is a small deposit, a mere 4 miles by 1.2 miles (7km-2km), divided into four blocks.  It is composed of hundreds of individual claims, both pits and underground tunnels, which are closely guarded and mined around the clock.  In 2017, the Tanzania government decided to build a wall around the Mererani Hills deposit, with only one gate, to prevent illegal mining and tax evasion.  Tanzania is a very mineral-rich nation, but also one of the most poverty-stricken.  It is estimated that only 5% of the global trade in Tanzanite directly benefits Tanzania, the remaining 95% is pocketed by wealthy mining corporations.

While “Tanzanite” is suppose to be from Tanzania, a similar-looking variety of blue-purple Zoisite has been found in Pakistan and is often marketed as Tanzanite too.  Similarly, blue-purple-pink Zoisite found in the United States is nicknamed “Prairie Tanzanite.”