Demantoid 101: Origin, Color, Value
Demantoid Garnet is a gorgeous stone, isn’t it? It has such high dispersion that its diamond-like name is perfect for it. And of course the nicest Demantoid Garnet colors are sourced from Russia. The vibrant apple greens and emerald greens, as we call them in the trade, are not to be found anywhere else in the world. Namibian Demantoid tends to be slightly lighter and more olive green than Russian demantoid (though it isn’t overly yellow). And the Madagascan stones, while warmer in tone than Namibian gems, are often overly dark with secondary browns. Both of these colors have their uses in designs as they can be blended with other more vibrant colors to offset or contrast them. But as a center stone or attention grabbing aspect of a jewelry design they are not ideal.
Russian demantoids only come from the Ural Mountains, not far from the city of Ekaterinburg, which itself is located pretty much in the middle of nowhere in this huge country. They are exported from there to Hong Kong or Bangkok, where they are cut and distributed. The number of vendors with the right connections that actually move the material out and get it ready for retail is very small. Maybe 3, 4 small businesses that I know of; they know each other and even work together as needed. Prices among them are comparable, and their color sorting is also the same.
Color availability ranges from a dark green that industry refers to as emerald green. It’s a dark but open color and a vibrant deep green, almost blueish although it doesn’t look anything like emerald (it looks close to tsavorite actually). The next lighter tone is usually referred to as apple green. It is my favorite color, though I also love the deeper and blueish emerald tones. Down the line from there are warmer and more olivy shades, all the way over to the more typical andradite color, a brown yellow tone that is actually extremely rare, but not valued very highly in the market.
Aside from that outlier, 80% of the production or more has olive tones in it, and only about 20% or a little less comes in apple and emerald green. Out of those two, emerald green makes up approximately one quarter. So in total, 5% or less of production is emerald green. And larger gems are (always) more rare than smaller gems. Practically the entire world’s production can be seen in Tucson at the GJX shows where the Russian vendors usually display.
Price wise, the emerald greens can fetch up to 10x the price as the other greens. Or more. In the melee sizes, prices are more fixed: the emerald greens are 2x the price of the apple green, 4x the price of the nicer olive greens and 8x the price of the more brownish greens (which I generally do not buy).
Generally demantoids are not treated, though there are heat treatments available for Russian stones that are sometimes used. So unless you have a cert, or direct information from the vendor, you cannot be sure any longer if they are heated or not. The heat treatment is with relatively low heat so it is less detectable in the lab.
And what of the famous horsetail inclusions? Those are typical of Russian origin, and you can see bits of horsetails in most Russian demantoids even when they are small. Those inclusions, and the apple or emerald color, actually tell you with 95% accuracy where your demantoid is from so for small stones, you would not need a certificate.