Tanzanite

Tanzanite is the blue to violet variety of the mineral zoisite. Its colour comes from small amounts of vanadium, and the finest stones show an intense, velvety blue with strong violet or purple flashes. Tanzanite is strongly pleochroic: untreated crystals show three different colours (blue, violet and brownish-yellow or burgundy) when viewed from different directions.

Tanzanite is found in only one place in the world, a small area about 7 km long in the Merelani Hills near Mount Kilimanjaro in northern Tanzania. It was discovered there in 1967 and introduced to the market in 1968 by Tiffany & Co., who named it after its country of origin, as "blue zoisite" was thought to be a poor selling name. Because supply comes from a single, limited source, tanzanite is often described as rarer than diamond.

Most tanzanite is mined as brownish or greenish crystals and is gently heated to remove the brown tones and produce the familiar blue-violet colour. This treatment is permanent and is standard throughout the trade. Some stones are coated to improve their colour, which is not permanent and should be disclosed.

Tanzanite is softer than many popular gems and has perfect cleavage, so it needs more care. Imitations include synthetic forsterite, glass, iolite and synthetic sapphire.

Tanzanite at a glance

Caring for tanzanite

Tanzanite (6 – 7 on the Mohs scale) has perfect cleavage and can crack or chip with a sharp knock or sudden temperature change. It is best for earrings, pendants and occasional-wear rings. Clean it gently with lukewarm soapy water and a soft brush. Never use ultrasonic or steam cleaners. Avoid acids, high heat and rapid temperature changes. Store it separately from harder gems in a soft pouch.

In folklore

The beliefs below are traditional folklore, included for interest. They are not scientifically proven, and nothing here is medical advice.

As a gemstone discovered only in 1967, tanzanite has little traditional folklore. In Tanzania, the Maasai people are said to regard the colour blue as sacred and give blue beads to women after the birth of a child, and tanzanite has become a popular gift for new mothers and newborns. It was added to the December birthstone list in 2002, the first new birthstone since 1912, and is the gift for a 24th wedding anniversary. It is associated with the zodiac signs Sagittarius, Gemini and Libra.

Tanzanite is traditionally regarded as a stone of transformation and spiritual awareness. Crystal healing lore holds that it calms an overactive mind, encourages compassion and communication from the heart, and supports intuition and meditation. It is linked to the throat, third eye and crown chakras.

Related stones

Zoisite, ruby in zoisite and thulite. Stones that can look similar include blue sapphire, iolite, amethyst, kyanite, blue spinel, synthetic forsterite and glass.

For the technically minded

Shop tanzanite beads

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