The demantoid garnet belongs to the large garnet family that is known for its dark red color. Not only is the demantoid garnet the most expensive in the garnet group, it is also one of the most precious of all gemstones and it is green.
Demantoid garnets come in varying shades of green from slightly yellowish green to brownish green to a blue green. The most precious garnet is a deep emerald green. The intense green colored demantoid garnet is considered most valuable but the lighter green gems have more fire and brilliance.
Demantoid garnets were first discovered in 1853 in Russia’s Ural Mountains on the western coast. The garnet is found in “clay, silt or gravel carried by rushing streams and deposited where the stream slows down”. A new discovery of demantoid garnets was found in Nambia in 1966 in a mine named the “Green Dragon”. They are also found in Italy, Iran, Afghanistan, Madagascar, the Congo and Korea.
Demantoid garnets are an expensive stone and most garnets found are less than 2.0 carats and even 1.0 carats are rare, most are smaller still. They have a higher dispersion of light than diamonds thus making the gemstone very beautiful but pricy as well.
In 2003, reports were made that demantoid garnets were being heat treated in order to improve its color. The heat treatment at low temperatures is not often detectable even by special gemological tests.
The Russian demantoid, more often than not has golden threads of inclusions that curve like the tail of a horse. The inclusions called horsetails are chrysotile, a type of asbestos that increases their value. Although inclusions in colored gemstones more often than not lower the value of the stone, the horsetail inclusions are distinctive, increase its value and mark it as a stunning example of a Russian demantiod garnet.