Tanzanite

Within the species zoisite lies a gemstone of drama and intrigue that’s consider, alongside the sapphire, to be of the finest blue stone in existence. Tanzanite, despite its scarcity, has not only gained a remarkable public awareness in a very short space of time, but has become an object of desire worldwide.

Tanzanite is a rare and beautiful transparent indigo-violet gemstone that is found in just one area of Tanzania and nowhere else. It was first discovered in 1967 and was recognised as a major gemstone when Tiffany & Co. introduced it to the international market. In an industry where colour is increasingly growing in importance for both jewellery makers and buyers alike, the tanzanite provides a more colourful and slightly more affordable option compared to a large blue sapphire.

The tanzanite can appear in a range of colours from a deep sapphire blue to violet-blue to soft lavender and lilacs, all due to the presence of vanadium. They often have a distinct pleochroism, allowing the specific hue of the stone to alternate when viewed from different angles. Occasionally the stone will be heat treated to produce a more intense blue colour. Considering the tanzanite doesn’t have the natural brilliance of a sapphire, it is often faceted into trillion, cushion and brilliant cuts to aid the stones lustre.

Sources:
Judith Crowe, The Jeweller's Directory of Gemstones (London: A&C Black, 2006)
Cally Hall, Gemstones (London: Dorling Kindersley, 1994)
Jaroslaw Bauer and Vladimir Bouska, A Guide in Colour to Precious & Semiprecious Stones (London: Octopus Books, 1983)