Australian Facetors' Guild Limited

  
Varieties of Garnet Stone

Garnets are historically one of the most important of the coloured gemstones, valued for their good hardness and excellent brilliance. The name garnet actually refers to a family of different gemstones. There are many different varieties of garnet, but no gemstone that is simply called "garnet".


Garnet Gemstones

All of the different garnets share a common crystal structure but vary in their chemical composition. Gemmology recognizes six common species of garnet based on their different chemical composition.


They are Pyrope, almandine, Spessartite, grossularite, uvarovite and andradite. In addition to these six species, there are a number of other garnet varieties that are distinguished in the gem trade, based on their colour or other special properties. Altogether there are at least 17 different varieties of garnet. 

Almandine (or Almandite) Garnet
Iron aluminium silicate, typically red with a violet tint.






Andradite Garnet
Calcium iron silicate, the andradite group includes demantoid, melanite and topazolite.



Colour-Change Garnet A mix of spessartite and Pyrope garnet. This rare garnet presents a colour change from brownish or orange in daylight, to rose-pink in incandescent light.


Demantoid Garnet

A type of andradite garnet that is the most valuable of all the garnets, due to its outstanding lustre and dispersion.


Calcium aluminium silicate, the Grossular group includes grossularite, hessonite, leuco, and hydrogrossular and Tsavorite garnet.


Hessonite Garnet
A type of Grossular garnet that is often called cinnamon stone for its brownish-red colour.


Hydrogrossular Garnet
A type of Grossular green garnet that is dense and opaque, resembling jade.


Leuco Garnet
A type of Grossular garnet that is entirely colourless.


Mali Garnet
One of the hybrid garnets, Mali is a mixture of Grossular and andradite garnet. It is green in colour with excellent lustre and dispersion.


An opaque black variety of andradite garnet.


Magnesium aluminium silicate, typically red with a brownish tint.


Rhodolite Garnet
One of the hybrid garnets, rhodolite is a mixture of Pyrope and Almandite garnet. Colours range from ruby-red to purple.


Magnesium aluminium silicate, typically mandarin-orange to orange-red.


Star Garnet
Garnets that display asterism (the star affect) are rare and have so far been found only in two places in the world (Idaho, USA and India).


Topazolite Garnet
A type of andradite garnet that is yellow to lemon-yellow in colour. Its similarity to yellow topaz is the reason for its name.


Tsavorite Garnet
A type of Grossular garnet coloured by chrome, resulting in a bright-green to emerald-green colour. The second most valuable of all the garnets.


Uvarovite Garnet
Calcium chromium silicate, typically emerald-green. It is rarely found in gemstone quality.




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