Unlike many well-known gemstones that have been in use for centuries, tanzanite’s history is relatively modern.
The common story of tanzanite’s discovery tells of Maasai herders who found blue crystals in the Merelani Hills near Arusha, Tanzania, while tending livestock in 1967. They notified a prospector named Manuel d’Souza, who promptly registered claims with the government to begin mining.
Initially, d’Souza thought he was mining sapphire gems, but the crystal was soon identified as a vibrant blue variety of zoisite—a mineral stone that had been around since the early 1800s.
Tiffany & Co. recognized this blue gem’s potential to rival more expensive sapphire and agreed to become its main distributor. Instead of publicizing “blue zoisite” —which sounded a little too much like “suicide” —Tiffany named the gemstone “tanzanite” to highlight its exclusive geographic origin and introduced it with a promotional campaign in 1968.
An estimated two million carats of tanzanite were mined before the Tanzanian government nationalized the mines in 1971. The government divided the mines into four sections, or blocks, in 1990. Tanzanite One Mining Ltd., the world’s largest tanzanite producer, holds the rights to Block C, which is larger than the other blocks combined.
An independent study from 2012 suggests that at a production rate of 2.7 million carats per year, Block C’s tanzanite deposits may deplete in as soon as 30 years.
Tanzanite may not have the long history of other gemstones, but with such limited supplies and rapidly growing popularity, it is highly prized for its rare beauty.