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Garnet

The lesser known January birthstone that is full of surprises

(A very rare ‘star’ garnet)

When people think of garnet they often regard it as a form of less expensive “ruby” but this belies the true character and value of this intriguing coloured gemstone. Garnet is a species of gemstone in its own right, derived from a collection of closely related minerals that come in a variety of colours. The etymology of the name garnet harks back to the ancient Latin word “granatum,” meaning dark red. Garnet, the January birthstone, has been used in jewellery and industry alike for millennia and it has experienced something of a renaissance in the twenty first century consumer market. As with most coloured gemstones it is the colour of a garnet that primarily drives its value. Garnet can be found in the full spectrum, from (the most famous and valuable) red and burgundy, through orange, brown, green and occasionally even blue and black. They are sometimes also found in chameleon like specimen that change colour according to the angle and type of light they are subjected to. Most garnets are shaped into faceted cuts, in order to enable them to be more easily worked into items of jewellery but some, very rare and expensive examples, including tsavorite and demantoid, are cut into shapes designed to optimise their carat weight. Most garnet exhibit fairly high degrees of clarity, by comparison with many other coloured gemstones, and many red garnet, including pyrope and almandine, are ‘eye-clean.’ That is to say they have no inclusions visible to the naked human eye. Some orange garnet do contain eye visible inclusions but when these form asterisms or stars they can actually significantly enhance the value of a stone.

(When most people think garnet they think red but the melanite variety is actually black)

It is very common for coloured gemstones to be enhanced in some way by either heat treatment or some other treatment. Intriguingly, garnet cannot be enhanced by any form of irradiation, heat or any other method and can only be found in their natural, unaltered state. Although natural examples cannot be enhanced, synthetic garnet are on the market and they are becoming more commonplace due to a steady upwards march in the prices commanded by natural garnet. As a result, certification by a reputable laboratory is the only way of guaranteeing a stone’s provenance. For many years garnet has been closely associated with ruby, largely due to a superficial similarity in their appearance but in truth the stones are completely different in origin and chemical composition. On occasions dealers have tried to pass garnets off as ruby, as the latter usually commands a higher price and this has lead to the unfortunate (and undeserved) reputation of garnet as the ‘poor’ man’s “ruby.” A tell tale sign that a stone is a garnet lies in its secondary colours, including orange, brown and green, which are not usually present in a ruby as these appear to be singularly vivid red in colour (although they occasionally contain purplish and bluish secondary hues). Another sign used by gemmologists to determine one from the other is the reflection of yellow and green light which occurs within garnet, versus the reflection of blue and red light found with a ruby. Ruby is also a doubly refractive stone, that is to say when an example scatters light a double rainbow effect can be observed.

(Blue garnet is among the rarest)

At 9 on the (1-10) Moh’s scale, ruby is a relatively hard stone in comparison to garnet’s 6.5-7.5. Garnets work with almost any design of jewellery and metal type but it is important to remember that, akin to emerald and many other coloured gemstones, it is relatively brittle so careful consideration needs to be given to the mounting and setting of these stones in order to avoid chipping or even cleaving (snapping) them. In all there are 6 sub-species of garnet that are formally recognised by leading gemmologists: andradite; pyrope; almandine, spessartite, grossularitye and uvarovite. Furthermore, there are another 11 recognised categories based upon colour and other unique qualities. Of the 6 sub-species the deep red variety pyrope are the most valuable, partly because they closely resemble rubies but also due to their high refractive index, giving them a beautiful sheen and high degree of scintillation (or ‘sparkle’). Production over the past decade of many varieties of garnet has actually been quite small so their value has started to increase. Grossularite is another sub-species of garnet that is becoming increasingly popular and it can be found in various shades of yellow to green but it is the andradite type that is the most lustrous of all garnet. Other varieties include Demantoid, which displays a unique olive to emerald green hue, Tapazolite, which is yellow or brownish yellow, and black Melanite, which is a lustrous, opaque black, sometimes simply referred to as black garnet. The final major variety of garnet is known as Uvarovite, which are deep emerald green in colour and among some of the most valuable garnets to be found on the market.

(Garnet complimented by a diamond halo and set in an 18K yellow gold ring)

Recorded use of garnet in jewellery dates back to at least 3,000BC, where ancient civilisations are known to have revered it as a force for healing and a giver of protective energy. Pre-historical depictions that are believed to be of garnet have been discovered in ancient bronze age Egyptian cave art. Ancient Roman, Greek and other classical scholars of antiquity often referred to garnet in their works. During the Crusades many warriors regarded garnet as a symbol of faith and truth and entrusted it as a talisman against the wrath of the ‘savage’ enemy. To this day garnet features in the inventory of many alternative faith healers, who continue to assert its therapeutic qualities and their perception that it is a powerful countermeasure to depression, anxiety and night terrors. Alternative medicine also maintains that other physical ailments may be alleviated by the proximity of garnet, including rheumatism, arthritis and some dermatological conditions, such as acne and skin sores. Naturally conventional medicine science strongly refutes the alternative claims outlined above but if nothing else they go to show the awe in which very many people regard this eminent coloured gemstone.

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