Tsavorite

Tsavorite is the vivid green variety of grossular garnet. It owes its colour mainly to vanadium, with some chromium. Found in Tanzania in 1967, it became known through a marketing campaign by Tiffany & Co. in the 1970s. It is noted for a colour that rivals emerald, for being more brilliant and for usually being clean inside; clean stones over one carat are rare.

Jewellery: Its vivid green and brilliance make it a gem for rings, earrings and necklaces. Like other garnets it has no cleavage and a hardness of 7–7.5, so it can also be used as an engagement ring stone. Collecting: Large, clean stones are collectors’ and museum pieces; the “Lion of Merelani” at the Smithsonian is the best-known example. An alternative to emerald: Because its colour can rival emerald, tsavorite is seen as an alternative for those looking for an emerald; it has higher dispersion than emerald and is usually cleaner.

It has a hardness of 7–7.5 on the Mohs scale. It scratches glass and steel; a steel knife cannot scratch it. Its specific gravity is 3.55–3.73 g/cm³.

Its best-known localities: Taita-Taveta area (around Voi and Tsavo), Kenya; Merelani Hills, Simanjiro, Manyara Region, Tanzania; Lemshuko (near Komolo), Simanjiro, Manyara Region, Tanzania; Toliara Province, Madagascar.

It is a vivid green or yellowish green stone, often clean and brilliant; compared with emerald it usually has fewer inclusions and splits light more strongly into coloured flashes (dispersion). It is singly refractive, that is, like other garnets it does not split light in two; its hardness is 7–7.5 and it has no cleavage. It may contain fluid inclusions, asbestos-like fibres and rows of negative crystals (crystal-shaped cavities inside the stone). Green glass and green YAG (a laboratory-made material with the garnet structure) have been used to imitate tsavorite; tsavorite itself has not been synthesised.

On the “street to diamond” value ladder it sits on step 7 of nine: Precious stone. Colour matters most for tsavorite: vivid, saturated emerald green is the most sought after. Large stones are rare: clean tsavorites over one carat are scarce, so size raises value quickly. Clarity and cut also count; tsavorite is usually clean and normally receives no treatment. Because it has not been synthesised, the main risk is imitations such as green glass and YAG, so a laboratory report confirming that a stone is natural tsavorite is important.

Today crystal-therapy websites claim that tsavorite is linked to the heart chakra and increases feelings of love, compassion and generosity. The same circles say that tsavorite supports the immune system and metabolism, cleanses the body and brings luck and abundance. There is no scientific evidence that tsavorite increases love, compassion or generosity, supports immunity or metabolism, cleanses the body or brings abundance. Tsavorite was found only in 1967, so it has no tradition of belief reaching back to ancient times. This section reports beliefs; it is not health information. There is no scientific evidence for these claims and no stone replaces medical treatment.