From top:
1. Cone-shaped pendant set with spessartite, gold and silver, designed by Silvia Marzola and produced by Bruni Bossio, winner of the special prize for originality in Hommages 03.
2. Roma ring in white agate set with mandarin garnet, diamonds and gold from Sanalitro
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STORY KEITH ANDERSON
Unearthing a wonderfully rich looking stone.
GARNET is a wonderfully rich looking gemstone. For some, if the garnet loses its lustre, it is a signal of impending doom. For Christians, the red garnet symbolises Christ's blood. For Muslims, garnets illuminate the fourth heaven. In more modern times, garnet has become the birthstone for January.
Garnets are divided into:
a) Pyralspites, consisting of pyrope, almandine and spessartite; and
b) Ugrandites, consisting of uvarovite, grossular and andradite.
What separates a Pyralspite from an Ugrandite is the chemical formula of the gemstone. Within the Pyralspite group, the varieties are also broken down according to their dominant colouring element.
Pyralspites
Hear the word 'garnet', and what invariably goes into your mind is the image of the deep red almandine and pyrope garnets belonging to the pyralspite family.
Almandine is a dark, slightly brownish or violetish-red stone. Pyrope tends to have less brown in it. Fine pyrope may be confused with a dark ruby, but medium quality looks much like almandine.
Spessartite garnets, also known as spessartine, are the orange to red-orange variety often colloquially referred to as 'root beer' coloured garnets.
Pyrope, almandine and spessartine are the 'traditional' boundary definitions within the Pyralspite family. Lesser-known variations have now been identified. Some of these include:
Umbalite - An attractive light pinkish-purple garnet that is a mixture of pyrope, almandine, with small traces of spessartine.
Malaia - A red-orange to pink-orange variety that is a mixture of pyrope, almandine and spessartine. Malaia garnets are lively gems that exhibit sparkling red flashes.
Rhodolite - An unusual member of the pyrope-almandine series, this material shows fine purple colours that are reminiscent of raspberries. Rhodolite has become very popular in recent years and is often cut in all manner of fantasy style cuts.
Ugrandites
Ugrandites, the other half of garnet, is made up of grossular garnets, uvarovite, mali and andradite which vary only by small differences in their chemical composition. Tsavorite, a grossular garnet that is a stunning green, stands tall as one of the most sought after and beautiful members of the garnet family.
Uvarovite or chrome garnet is also a beautiful green-coloured garnet, occurring in fine crystal clusters. It comes in small sizes and is not frequently seen in jewellery; although uvarovites of a top emerald green hue are increasingly sought after.
Related to Uvarovite are the rare Afghani Imperial Garnets and the African green garnets. The former is bright and lively with stunning orange colours.
Demantoid Garnet
The final member of the Ugrandite family is Andradite. Named after the Brazilian mineralogist JB de Andrada e Silva who wielded a loupe way back in the 18th century, it comprises demantoid, melanite and topazolite.
The rare and dazzlingly bright grass green sub-variety of Andradite is demantoid garnet. One of the rarest and most desirable of all coloured gemstones, demantoid was unearthed for the first time at the end of the 18th century. The name derives itself from 'diamond-like', due to its fantastic adamantine lustre, which yields even higher fire than diamonds!
Rarely, some demantoids show a colour change from green to orange. This colour change, combined with its high fire and brilliance, makes the demantoid a unique variation of an already rare gem.
Some demantoid garnets from Russia have fibrous inclusions that can form beautiful patterns similar to the tail of a horse, hence the name 'horse-tail' inclusions. Demantoids with such inclusions are particularly valued and this is a fine example of an inclusion that adds rather than detracts from the value of a gemstone.
If you know you want a piece of demantoid garnet, don't wait too long. If the current seams of demantoid run out, you could be waiting another century before new stocks become available. After all, the greatest and most precious things on earth don't last forever.
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