Tanzanite, scientifically known as blue zoisite, is a relatively recent addition to the world of gemstones. Unlike diamonds or rubies, which have been worn for centuries, tanzanite’s story only began in 1967. A story of chance; the setting — the foothills of the famed Mount Kilimanjaro. The protagonist — a young Masai tribesman. Jumanne Ngoma had stumbled upon a cluster of striking blue-violet crystals. At the time, there had been no previous report of zoisite with this color, so it was assumed to be sapphire. Ngoma took what he believed were sapphires to local traders, and the stones eventually made their way to Manuel D’Souza, a prospector from Goa.

D’Souza, also puzzled by the gem’s unique mix of blue, violet, and sometimes purple hues, sent the stones to gemologists in the United States for further testing. Experts at Tiffany & Co., working alongside the Gemological Institute of America, confirmed that the crystals were in fact a new blue variety of zoisite—not sapphire.

In 1968, Tiffany & Co. renamed the stone Tanzanite and introduced it to the world as the “gem of the 20th century.”

In 2002, the American Gem Trade Association added tanzanite to the official birthstone list. Tanzanite joined turquoise and zircon as the official birthstones for December.