Garnet is a group of more than ten different gemstones of similar chemical composition. The main differences are slight variations in colour, density abd refractive index. Spectacular finds, especially in Africa, have enhanced the traditional image of the garnet with a surprising number of hues. Although red continues to be its principal colour, the garnet also exists in various shades of green, a tender to intense yellow, a fiery orange and some fine earth-coloured nuances. The only colour it cannot offer is blue.
Garnets are much sought-after and much worked gemstones – the more so because today it is not only the classical gemstone colours red and green which are so highly esteemed, but also the fine hues in between. Furthermore, the world of the garnets is also rich in rarities such as star garnets and stones whose colour changes depending on whether they are seen in daylight or artificial light.
There is its good hardness of 7 to 7.5 on the Mohs scale. With a few minor exceptions it applies to all the members of the garnet group, and it is the reason for the excellent wearing qualities of these gemstones. Garnets are relatively insensitive and uncomplicated to work with. A further plus is their high refractive index, of between 1.7 and 1.89, that gives the garnet’s great brilliance.
Garnets have been known to Man for thousands of years. Noah, it is said, used a garnet lantern to help him steer his ark through the dark night. Garnets are also found in jewelry from early Egyptian, Greek and Roman times. Early explorers and travelers liked to carry a garnet for it was popular as a talisman and protective stone, as it was believed to light up the night and protect its bearer from evil and disaster.
Its spirited red, often with a slight brownish nuance, was a gemstone colour much in demand in the 18th and 19th centuries. Garnets from a find in the north-eastern part of the former kingdom of Bohemia – small stones of a wonderful hue – were world-famous at that time. In Europe, they were worked into jewelry a good deal, especially in the Victorian period. And today too, garnets are still found in former Czechoslovakia and set close together according to the old tradition.
A further garnet variety, also red, is the rhodolite. a mixed crystal of almandine and pyrope. This popular garnet is of a magnificent velvety red with a fine violet or raspberry-red undertone. Originally found in the USA, it now comes mainly from the gemstone mines in East Africa, India, Russia and Sri Lanka.
The specialist world was amazed in 1991 by the fantastic find of a type of garnet that had been very scarce until then. At the Kunene River, on the border between Namibia and Angola, a deposit of radiant orange to red ‘spessartites‘ was discovered. The spessartite was originally named after the site of a find made in Germany. Spessartites had led a quiet, shadowy existence as stones for gemstone lovers and collectors until that momentous discovery in Namibia. There were hardly any used in jewelry up until this time because they were so rare. But this new find changed the gemstone world with the addition of this unusually fine, intensely radiant orange-red gemstone.
Under the trade name ‘mandarine-garnet‘, this wonderfully orange noble garnet gained world-wide recognition but the mine in the quiet hills of Namibia was only able to be exploited for a few years. That is, until another deposit was discovered, this time in Nigeria.
Several green varieties of garnet are also known. First there is ‘grossularite’, created by nature in many fine tones of yellow, green and brown and esteemed for its many fine interim hues and earth colours. Here too, there was a spectacular find: in the final year of the 20th century, extensive grossularite deposits were discovered in Mali. These Mali garnets captivate us with their great brilliance.
Probably the best-known green garnet is the tsavorite or tsavolite, which also belongs to the grossularite group. Tiffany’s in New York gave this name to the previous emerald-green stone which was discovered in 1967 by a British geologist, Campbell R. Bridges, in the north-east of Tanzania – after the place where the discovery was made, near the Tsavo National Park. The green of the tsavorite runs from vivid and light to deep and velvety and, like all garnets, it has particularly good brilliance
The star of green garnets is the rare demantoid. Its brilliance is positively tremendous, even greater than that of the diamond. Russia’s star jeweller Carl Fabergé loved the brilliant green garnet from the Urals more than anything else, and used it in his creations. Meanwhile, the demantoid is no longer quite as scarcedue to some new finds in Namibia. Demantoids from Namibia are of good colour and brilliance, but they lack one tiny feature: the so-called ‘horse-tail inclusions’. These fine, bushy inclusions are the unmistakable, typical feature by which a Russian demantoid is recognised.