Garnet: lights the way

Deep red is generally the colour that comes to mind when thinking of garnets, but the family actually encompasses gems of nearly every colour, bar blue.

Some garnet varieties change colour in different lights and some exhibit stars. The blood-red coloured garnet is known as Pyrope garnet, whose colour is due to chromium. Its best examples come from Bohemia and South Africa, where they are found as accessory minerals in diamond mines.

Other reddish varieties of garnets include the Almandine garnet, which ranges from red to orange to brown. A cross between the pyrope and almandine garnet is the Rhodolite garnet, which is a beautiful purple-red colour. In Victorian times, garnets were commonly used in jewellery, and often cut in a domed style called a carbuncle to lighten their colour.

Grossular garnets (grossularites) occur in red, orange, yellow, green and even colourless shades. Well-known members of the grossular garnets are Hessonite (orange to yellow) and Tsavorite (green), although many other colours come under the Grossular heading. Spessartite (or spessartine) garnets are deep orange, due to the presence of iron and manganese impurities.

A particularly valuable and rare variety of green garnet is the Demantoid garnet, the finest examples coming from the Ural mountains in Russia and found in the 19th century jewellery favoured by the Tsars.

The name 'garnet' is derived from the Latin ‘granum’ meaning grain. This is a reference to the gem’s typical cabochon-cut shape, which looks like the red seeds of a pomegranate.

The use of garnet dates back to biblical times, with several references to the gem in the Bible. Legend has it that a large garnet adorned a pedestal in the middle of Noah's Ark. The brightness of the stone was said to illuminate the sea, allowing the ship to travel safely through the night.

Talismans set with garnet were believed to protect warriors during war and bring them peace and tranquility when they returned. The gems were also set into signet rings, belt buckles and other personal objects of adornment to protect soldiers during battle. During the 1600s, garnet was said to halt the flow of blood, thus it was often used as a remedy for heavy blood loss.

More recent appearances of garnet include its inclusion in an ornate 19th century cabochon flower brooch owned by Jacqueline Kennedy Onassis. The piece fetched $US145,000 at a Sotheby's auction in 1996.

The garnet's continuing popularity lies in its natural untreated beauty, the extensive range of colours available and its brilliance, owing to its high refraction of light.

The grainy texture of garnets also makes them useful in the abrasives industry for smoothing and grinding objects.

With a rating of 7.5 on the Mohs' scale, garnet is a tough stone that will withstand everyday wear and can be set into jewellery pieces with minimal fuss. A simple cleaning regime of wiping the stone with a dry, soft cloth is sufficient to keep a garnet looking beautiful.
 

Fact Sheet 

• Hardness: 7.5
• Variety of: Contains compounds of silica, aluminum, calcium, iron and magnesium.
• Found: Throughout Africa, Europe, America, Asia and Australia.
 

Birthstones 

• Modern birthstone: Garnet
• Traditional birthstone: Lapis
• Mystical birthstone: Onyx
• Ayurvedic birthstone: Ruby