History and General Information of Green Demantoid Garnet

Andradite garnet mineral has three main varieties and they are demantoid garnet, topazolite garnet and melanite garnet. The beautiful brilliant green demantoid garnet is the most popular garnet in this group because of it's spectacular and exceptional brilliance and fire. No wonder it got its name demantoid which means diamond-like.

Demantoid garnet  which is also known as the famous green garnet was first found in the Ural Mountains of Russia in the year 1868. It soon became very popular with the Russian nobility. In fact small sized Demantoid gatnets set in jewelry was one of the striking features of the Edwardian jewelry. However, due to the softness and rare occurrence of the gem it slowly lost popularity.

But later on in the middle of 1900 this gemstone again got its dueful credit back, when it was discovered in mines of Namibia.

Chemical Composition of Demantoid Garnet

Andradite garnet chemical composition is calcium ferrous silicate (Ca3 Fe2 {SiO4}3). It's specific gravity is between 3.82 to 3.85 and refractive index range is around 1.89. This crystals hardness on Mohs scale is 6.5 to 7. This gemstone has a vitreous to sub-admantine polish luster.

Other Varieties of Andradite Garnet

Topazolite - The yellow topaz coloured garnet from this group is called topazolite. It is coloured by iron and is rarely used in jewellery.

Melanite - This is the opaque black garnet crystal that is no longer used in jewelry. The gem was used as mourning jewelry and in inlay work before the massive use of black Onyx and dyed Chalcedony. This garnet is coloured by iron and titanium.

Physical properties of Demantoid Garnet

Demantoid Garnet color

A fine quality demantoid garnet may have a color very close to the deep emerald green. One can also find demantoids in light and dark shades of colors of greenish yellow, yellowish green and brown.

Cut

Demantoid garnet is usually cut and faceted in round and oval shape for better durability. (because of its low hardness). But it is also found in fancy shapes like pear, rectangular etc.

Carat

Demantoid garnets are usually not found over a few carats in weight. Thus, it is often used in demantoid garnet jewelry with cluster setting of round cuts. However, due to its rarity large gems of over a carat is greatly demanded by gemstone collectors and lovers.

Clarity

The most striking inclusion of a demantoid garnet is the horsetail inclusion. These are curved radiating bundles of fibers and the presence of this inclusion  increases the value of the gem tremendoulsy. Though presence of this inclusion is  sure sign of its identity, many demantoid garnets are inclusion free and eye clean.

Price, Cost and buying guide of Demantoid Garnets 

One can buy a demantoid garnet in the price range of US$15 to US$500 and more. But ofcourse as the thumb rule gems of exceptional color and clarity can demand great prices. Also if the demantoid garnet has its typical horse tail inclusion then the cost rises. Eg. A eye clean 1.25 cts good green color demantoid garnet costing around USD 150 per carat, with its typical horse tail inclusion would be  costing USD 1000 per carat.

Markets and producers

Other than demantoid garnet gem stone being mined in Russia this garnet is also found in the mines of Africa (Namibia), Italy, Greece and Mexico.

Treatments done on Demantoid Garnet

It has been heard in the market that some mineral specimens of natural demantoid garnet roughs are heat treated to enhance their color and clarity. But there are no recorded data or proof of the same.

Simulants

Demantoid garnet may be confused with spinel, zircon, apatite, tourmaline and emerald.

Interesting trivia

Due to this gemstone's quite soft and brittle nature it becomes important to use it in jewelry like earring and pendants rather than in jewelry like rings.

Demantoid garnet is also called as green garnet .

Reference

1) Webster
2) Gemmology by Peter G.Read
3) Handbook of Gem Identification -   Richard  T.Liddicoat, jr
4) Gems and Crystals - From the American  Museum of Natural History - Anna S.Sofianides  and George E.Harlow.