Gem of the Month: Garnet

The name garnet is from the Latin word “granatus” arising from the similarity of the typical small red garnet gemstones to the dark red seeds of the pomegranate fruit. Even today, most people only think of the typical rich red colour of “Bohemian Garnet” but if you dig a little deeper, you will be amazed by the wide variety of colours – some very rare with a price tag to match.

Gemmology matters: Garnet is a silicate mineral and are relatively common in highly metamorphosed rocks and in some igneous formations. They form under the high temperatures and/or pressures that those types of rocks must endure. The composition of most garnets is A3B2(SiO4)3 where A represents calcium, iron, magnesium and/or manganese and B represents aluminum, chromium, iron and/or manganese (rarely vanadium, titanium, zirconium and/or silicon). It is often said that the only colour not available in garnet is blue – however, it seems that some Madagascan garnet found recently may be termed blue (see this article by Alan Hodgkinson). The spectacular green colour of the tsavorite and demantoid varieties of garnet have to be seen to be believed – rare and expensive but worth the money to many keen collectors and gemstone lovers. The bright “fanta” orange colour of spessartite has made this another keenly sought after variety of garnet and one which is becoming difficult to source.

The high refractive index of garnets gives them great brilliance as a cut gemstone and the lack of cleavage and a hardness of around 7 on the Moh scale mean they are relatively durable for most types of jewellery. Garnets are usually recognized by their form, color and hardness with garnet varieties being distinguished by their refractive index, absorption spectrum and colour although some training in gemology is recommended as garnets form a particularly complex group.

Mythology and Lore: Garnets have been used as gemstones for many thousands of years and in ancient times were known as “carbuncles”. Legend has it that Noah used a lantern from garnet to safely steer his Ark through the darkness of the night. Garnets are found in jewellery from ancient Egyptian, Greek and Roman eras – the presence of garnet jewellery in burial sites indicates that they were valued as protection in the afterlife .

During the Middle Ages, it was believed that these red stones would stop bleeding. Many people believed that garnets were helpful in preventing and curing blood disorders and infections. In earlier times, garnets were exchanged as gifts between friends to demonstrate their affection for each other and to ensure that they meet again. Many travellers wore garnets for protection as it was believed in old times that garnets illuminate the night and prevent their wearer from any sort of evil. Garnet is the birthstone for January and the zodiac stone for Aquarius. Garnet may be given on the 2nd and 6th wedding anniversary.

Alternatives in Red: Although as mentioned above, garnet comes in a wide variety of colours, alternatives in red will be discussed here as this is the more widely known colour for garnet. The obvious candidate is ruby with red spinel coming a close second. Either of these two alternatives in fine quality will be far more expensive than the traditional red garnet which may have varying overtones of brown in contrast to the pure red of these much rarer gems. The almondine and pyropes varieties of garnet can have fine deep red to purplish colour and will be priced at a higher level reflecting the better colour quality but most will not compare with the best rubies or red spinel. For stones of deep pink to red colour, rhodolite garnet is a good choice and may compare with lighter colour ruby or deep pink sapphire. Although more expensive, ruby, spinel and sapphire are harder than garnet and will be more durable than garnet.

Links of interest:
Gem by Gem article on Garnet – International Colored Gemstone Association
Mineral Galleries article on the Garnet group of minerals
Bernadine Fine Jewelry – Garnet mineral information page by Mineral Miners
Spessartite Buying Guide – Palagems.com
Univ Texas Gem Notes on Garnet

While garnets (red in colour) are rarely found at our mine, they do occur in the area – they are generally found more frequently east of Glen Innes and upstream of our mine on the Reddestone Creek. However, garnets are a very popular gemstone and in the interests of offering more choice to our customers, Aussie Sapphire have a range of garnet gemstones and jewellery available. Some time ago, we imported a parcel of very high quality spessartite garnet from Nigeria – this has been split with some sold in the rough, some cut and some used in our fine jewellery. Please see our Ebay Store for a range of garnet and spessartite gems (see an example in photo at left). We also have a range of affordable garnet jewellery – see photo below for some examples of some pieces in silver which have proved very popular (see here for a selection from our catalogue or email us if you would like to make a specific enquiry).

That is all for now from Aussie Sapphire.

Advertisements

2 Responses to Gem of the Month: Garnet

%d bloggers like this: