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Demantoid Garnet Gemstone

A rare, green Garnet with amazing brilliance.

 Rarer than possibly any other Garnet, the green Demantoid is a member of the Andradite family.

It is the most brilliant of Garnets in the sense that it displays the most brilliance and the most dispersion (brilliance being the technical word for the sparkle caused by the return of white light from within the gem, and dispersion being the breaking down of white light into the colours of the spectrum). In a sparkling competition, Demantoid would compete head on with Diamonds and its name derives from Dutch for “Diamond like”. Its luminosity is so intense that it is even said to sparkle in the dark!

Interestingly, it was first discovered in the Ural Mountains of Russia, some 30 years after the discovery of Alexandrite in the same area.

The Russian jeweller Carl Fabergé was fascinated by the gem, and soon afterwards Tiffany’s started setting the gem into jewellery. In the early 1920s, mining for the gem in the Ural Mountains came to a halt and the gem pretty much became extinct until it was rediscovered in Namibia in December 1996.

Now, just as you are starting to get to grips with how gemstones are valued, Demantoid blows a hole in your confidence! The Namibian Demantoids are truly gorgeous and almost inclusion free. However, the original Russian Demantoids often had inclusions caused by the presence of Byssolite fibres. These were known as “horse tail” inclusions and added to the uniqueness of the gem. Therefore, breaking the normal rule of “fewer inclusions = higher price”, the stunning, inclusion-free Namibia Demantoid Garnets, are worth less per carat than the heavily included Russian Demantoid!

In 2009 there was probably one of the most important discoveries ever of Demantoid Garnet in the North West of Madagascar. Near a small seaside village known as Nosy Faly, is one of the strangest mining setups you are likely to find. The gem has been discovered in a mangrove swamp. That wouldn’t be too unusual if it was inland, but this swamp is on the coast.

Every day, just like in the UK, the tide rises and falls. When the water recedes, the mines look like any other artisanal mine, with bamboo fences and hand made winches, but as the tide races in, the miners rush to the nearby hill sides and within less than an hour their whole mining set up is one metre under water. There are said to be 600 or 700 small mines in an area less than a third of a mile square and I have been told that some of these mines are now some 10 to 20 metres below the surface.

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Demontoid garnet.