Demantoid Garnet
Demantoid Garnet
Demantoid is the green gemstone variety of the mineral andradite, a member of the garnet group of minerals. Andradite is a calcium- and iron-rich garnet.
It is the most expensive and rare of garnet gemstones, with fine specimens commanding prices of thousands of dollars per carat (thousands per gram).
Demantoid garnets are very rare stones that are only mined a few places in the world. Demantoids are valued for their rarity, their beautiful sparkle and their unique form. The gem was first discovered in Russia and the name is derived from its diamond-like adamantine luster.
While the color of demantoid never equals that of the finest emerald, an emerald-green is the ideal. The color should be as intense as possible, without being overly dark or yellowish green. The color of demantoid is believed to be due to chromium. It should be noted that demantoid’s fire is best seen in the lighter, less saturate gems.
Demantoid by definition is always green, but the exact shade ranges from a very strong yellowish green to nearly the color of a fine emerald. Many stones have a brownish cast. Stones with more intense green coloration are more highly valued, but lighter stones display substantially more fire. The choice of stone color or fire can therefore be a matter of personal preference, with some preferring the less valuable but more lively yellowish-green stones.
While garnets have been known since ancient times, the demantoid variety was not discovered until 1853 in Russia’s western central Ural Mountains. The find was about 110 kilometers north, northwest of Ekaterinburg along the Bobrovka River near the village of Elizavetinskoye. This is an alluvial deposit. A second find is 75 km. south of Ekaterinburg on the Chusovaya and Chrisolitka Rivers southwest of the village of Poldnevaya. Deposits are also found underground up to 3 meters deep in the demantoid place.
In terms of clarity, demantoid is relatively clean. Thus when buying one should expect eye-clean or near-eye-clean stones. Demantoids often contain radiating needle inclusions that are termed “horsetails. Some demantoid garnet is heat-treated to improve the color. The resulting stones are stable under normal wearing conditions.