Wednesday, May 29, 2013

Gemstone of the Week: Demantoid


(Demantoid image found on jogshow.com)

Demantoid is a very rare variety of Andradite Garnet.  It was discovered in 1851 in the Ural Mountains of Russia and is considered to be one of the rarest varieties of Garnet (the blue Garnet being the most rare).  Demantoid is the green variety of Andradite and it's name comes from the old German word "Demant" meaning "diamond." It was named this because it has a very high brilliance giving it a diamond-like appearance.  Being as it is a Garnet, it has a fairly good hardness.  It's hardness ranges from 6.5-7.  It is a translucent to transparent gemstone and has a vitreous luster. An interesting thing to note is that Demantoids were often used in antique Tiffany jewelry from the mid to late 1800s into the early 1900s, so if you collect antique jewelry you should not automatically assume that the beautiful little green gems in your jewelry are Peridot as they could possibly be Demantoid (you will need to have an appraiser or gemologist look at the piece to determine which stone it is).  Demantoid Garnets can command a very high value depending on the quality, size, and what shade of green the stone is.  You can find the current per carat value of Demantoid on GemVal's website.  Demantoid may be found in a few locations in: Afghanistan, Argentina, the Canadian provinces of Quebec and the Yukon Territory, China, Germany, Iran, Italy, Japan, Madagascar, Mexico, Nambia, Russia, Slovakia, Spain, Sri Lanka, Switzerland, Tajikistan, and the state of California.

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