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More on Garnet

The birthstone for January is generally acknowledged to be Garnet. Unlike some other months, there are few alternative stones for January although some sources list emerald as the “mystical stone” for January.  However, garnet is a very versatile gemstone in its own right with a beautiful range of colours available.

tsavorite_suite.jpgSince we have already covered Garnet in our usual “Gem of the Month” format, we will explore some of the varieties of garnet in this month’s article.  An example of one of the more unusual varieties is tsavorite seen in the photo at left from Palagems in their Tsavorite Buying Guide.

Garnet is a group of minerals with similar chemical composition, physical properties and crystal structure.  There are six species of garnets recognised although many gems lie on a substitution scale between species making a positive identification somewhat challenging in many cases.  See the Garnet Factsheet on Mineral Miners for more discussion on garnet species and how to distinguish them.

  • ALMANDINE:  Colour is typically a deep, rich red – less valuable specimens have more brown.  Sources:  Brazil, India, Madagascar, Sri Lanka, U.S. in Arizona, Idaho, New Mexico, Utah, Arkansas and Kentucky.
  • PYROPE:  Colour is usually deep, rich red or variations on this.  Sources:  Australia, Czechoslovakia, South Africa – Zimbabwe and Mozambique.
  • SPESSARTITE:  Colour is ideally bright orange but ranges from reddish orange, red, reddish brown, to brown.  Sources:  Brazil, Namibia, Pakistan, Sri Lanka, US.
  • ANDRADITE:  Colour usually ranges from green, yellowish green to greenish brown and may occur in black.  This species includes the highly sought after demantoid garnets.
  • GROSSULAR:  This species ranges widely in colour from colourless to black with almost all colours in between (red, green, pink, yellow, etc).  This species includes the rare and valuable tsavorite garnets.
  • UVAROVITE: This quite rare species of garnet is dark green and often found as fine crystal clusters (sometimes referred to as drusy because of the small crystal formations).

For more reading on this, I recommend the Garnet page on the Gemology Project – this is a new resource associated with the Gemology Online forum so it is highly recommended for anyone interested in gems.

Due to the complexity of the garnet group, there are quite a number of individually named gem varieties.  Here are just a few:

  • HESSONITE: this garnet falls into the grossular species and occurs in yellow, orange and brownish colours.
  • RHODOLITE: This rose-red to purple garnet is part-way between Almandine and Pyrope – closer to pyrope than the Mozambique type garnet which is also a pyrope-almandine garnet of a deep red shade.
  • TSAVORITE: Medium, intense green to slightly yellowish green.  This rare and valuable gem is found in Kenya around the Tsavo National Park area for which it is named.
  • DEMANTOID:  Another highly sought after gem – the best examples will show intense green colour and “horsetail” inclusions.

The commonly found red garnet (likely of pyrope-almandine type) are very affordable and used in jewellery all around the world.  A range of these in calbrated sizes are available in our online shop for those looking to use them in jewellery at the more budget end of the scale.  A little higher up the scale is rhodolite and spessartite.  Spessartite in particular is becoming very popular and with a current shortage of rough, they are certainly not a cheap option.  For those who want only the best, we suggest you consider the more rare varieties of garnet such as demantoid, tsavorite or colour change garnets (including the new blue varieties from Madagascar).

demg107.jpg A classic example of a demantoid garnet from the Ural Mountains in Russia – clean except for the diagnostic “horsetail inclusions” and available from Mineral Miners.

spess-b.jpgThe picture at right shows some spessartite cabochon cut from rough we sourced from Nigeria.  We have spessartite rough available online now and we hope to list some of our faceted and cabbed gems as soon as possible.  These gems can show some real fire and make fantastic pieces of jewellery.

I hope this article has inspired you to consider garnet for your next gemstone purchase – there is certainly something for everyone in this fantastic range of gems.