Tanzanite

Found in one place on earth

Discovered in 1967 in the foothills of Kilimanjaro, tanzanite is one of the rarest gems in the world.

Hardness: 6 to 7 on the Mohs scale
Colors: Violet blue to blue violet
Birthstone: December
Family: Zoisite

Chapter one

A modern discovery

Tanzanite is mined only in the Merelani Hills of northern Tanzania. It was named for the country it comes from and introduced to the world by Tiffany & Co. in 1968.

According to Maasai legend, lightning struck the slopes of Kilimanjaro, setting the hills ablaze and turning brown stones into vivid blue crystals. Tiffany & Co. introduced it to the world in 1968 as “the most beautiful blue stone discovered in 2,000 years.”

It comes from one small area in northern Tanzania.

Chapter two

Color that shifts

Tanzanite is trichroic: it can show blue, violet and burgundy depending on the angle and the light. Most tanzanite is gently heated to bring out its blue.

Tanzanite is pleochroic: in daylight it glows sapphire blue, and under warmer light it shimmers violet or burgundy. Its only source is a narrow strip of land a few kilometers long, so geologists estimate the world’s reserves could be depleted within a few decades. Symbolically, it stands for transformation and new beginnings.

Turn it in the light and the color changes.

Chapter three

Wear and care

Tanzanite is softer than sapphire, so store it on its own and clean it with mild soapy water.

Worth knowing

Tanzanite is 1,000 times rarer than diamond.
Heat reveals its famous blue; in nature the crystals are usually brown until warmed.
Tanzanite became a December birthstone in 2002, alongside blue zircon and turquoise.
Tiffany’s first slogan for tanzanite was “Born of fire, from the heart of the Earth.”
Its only known source is a strip of land near Kilimanjaro a few kilometers long.