I finally had a chance to go to Sri Lanka, the island of gemstones, a few weeks ago. As a passionate gemologist I hoped I would be able to get wonderful sapphires at a super low price when buying directly from the miner.
I had prepared myself well. Read all available articles about sapphires, checked European suppliers and prices. Checked and rechecked all the sapphires I could get my hands on, so that I knew exactly what to look for in the field.
I had also talked with lots of colleagues in the gem industry, who had recommended me trustworthy dealers. The first ones I went to, kept giving me glass, to check if I could see it was glass, and they asked me 3 times more pr. Carat than the gem dealers in Antwerpen. What a waste of time.
But finally I found a dealer, who had beautiful, beautiful stones. All in amazing colors, fantastic cuts and he could recut any stone, into the exact measurements I was looking for. I was in heaven. I spent 1 full day going through all his stones, took my equipment to his show room, and made gemological tests of the gemstones I was most fond of.
So what did I look for?
We grade gemstones like diamonds, using the 4 C’s.
But contrary to when buying diamonds where one looks for the perfect combination of the 4 C’s, when buying gemstones color is absolutely the first priority. COLOR IS KING. When grading color we look for the HUE, which is the basic color of the gemstones, it can be described as purplish pink, orangy yellow, greenish blue. We want as much of the real color as possible. To make an example we don’t want pink sapphire, to be purplish pink or orangy pink. We want them to be pink. Pink-pink. The second factor of a gemstones color is saturation, how much of the color is in the stone. Is it light, medium, vivid or intense. The more color the better. So, a pink sapphire, that is described as intense pink, is much more valid than a pink sapphire described as light purplish pink.
The Clarity is not as important in gemstones. For diamonds, we want them to be with as little inclusions as possible, and in gemstones we would also prefer to have an inclusion free stone, but it is not always possible. To take an example, emeralds almost always have inclusions. So then you want to find a stone with as little visible inclusions as possible.
The cut of gemstones is almost always native cut, which means that the cutter has cut the stone to show the best color. So, it can be a bit off centered, high or low pavilion, but it should always be symmetrical. It is really a matter of taste, some people don’t mind if the cut of a gemstone is not perfect. But I look for symmetry, sharp well-proportioned facets and a beautiful stone, which shines and has life.
Carat of a gemstone is the same as of carats in diamonds, 1 carat is 0.2 grams. But some gemstones are heavier than diamonds, so they will be physically smaller with the same carat weight. Quite important to bear in mind if you are looking for a gemstone to replace a diamond in a piece of jewellery.
Treatment is a very import part of gemstones. Most gemstones are heat treated to bring out the color. Some gemstones, like the famous Tanzanite, was found as a brownish grey stone, but when heated it turned out to have a beautiful violet-bluish color, which is super sought after. Blue topaz is also a dull greyish color when mined, but after being heat treated it gets the vibrant blue colors we all love. There are many treatments of gemstones, and it will normally be described on the Certificate of the gemstone. Some gemstones don’t show a trace of treatment, but it is necessary and legally required for anyone selling a gem, to disclose the treatment procedure it may have received. This doesn’t always happen, so it is important to know what to look for.
There are different treatments used especially for gemstones. The most used is, as mentioned earlier, heat treatment.
Another treatment is lattice diffusion, which is normally used for rubies and sapphires, where beryllium is diffused through the gem, and makes it change color. This treatment is very difficult to detect, which is also a good reason for only buying gemstones from a known and tested dealer.
Fracture filling, is a treatment used mostly in diamonds and emeralds. It is a way of filling fractures naturally present in gemstones. The fractures are being filled with high-lead-content-glass, and sometimes even a colored agent to make, for example, the emeralds look greener. It is quite easy to detect for an experienced gemologist under magnification, as the filled fracture will have a different sheen than the rest of the stone.
So over all it is quite challenging but fun to buy gemstones directly from the source. My advice is to not spend too much money on a single stone. You might be lucky or unlucky. So make sure that you love the stone, especially the color.