Diamonds, rubies, emeralds, sapphires: which is their value? How to recognize them? Some people buy them to make up for something, someone to love, for others is a safe haven investment. Whatever the motivation, the opinion of an expert is crucial. Mainly because when it comes to diamonds, there are parameters which are a kind of list of basis for the listing, but for colored gemstones such as emeralds, rubies and sapphires the matter is not simple. What to be careful and what criteria adopted for the selection, is explained by Pio Visconti, Italian Gemological Institute lecturer, consultant of many regional entity and owner of the Gemological Centre based in Valenza. The proof that it is a famous gemologist, lies in the fact that his skill is cited as a guarantee in the auction catalogs, in case of its certification of the jewel. «How to evaluate a stone? If you were to buy a Rolex goes from the authorized dealer or call for a friend who bought it on the subway?», says in this interview with Gioiellis.com .
Question. Which among the famous four C carat, color, clarity and cut, it is more important when choosing a diamond?Answer. The criterion that must prevail, in my opinion, is cut. Of course weight, color and clarity are important, but because spending a stone IF 40 points and 70 points maybe a Vs2 is quite similar, the fact remains that when the diamond is set must shine on the frame, it must be a mountain of light, as the ancients said, and this can only be achieved with a good cut.
Q. But those who are not in the industry how can recognize a good job? They only rely on their aesthetic sense?
A. In the certificate are visible the numbers that refer to the values of the upper part, for example 57 %, and the height of the crown 14%. To the customer does not say anything and that is why beside is written the analyst’s judgment: excellent, good, average, as proportions or as accuracy. Ultimately, I’d recommend a diamond cut-out great, because the other criteria are linked to the price.
Q. What do you do if the certificate does not exist?
A. I do have a question: if you were to buy a Rolex goes from authorized dealer or call for a friend who bought it on the subway?
Q. Many well-known brands are keen to highlight the exclusive use of certified diamonds, but there is the risk of receiving the certificate of another gem?
A. Anything can happen, but ruining his reputation for a non-transparent behavior for little gems of value is not worth it, especially since it takes very little to turn into a business catastrophe. In cases of very rare stones, the diamond is sealed with his certificate inside, even in the last decade is increasingly the request of engraving the certificate number on the girdle of the stone itself.
Q. The race to the certification also depends on the remarkable technological developments in producing synthetic diamonds that are derived from carbon yes, but made in a laboratory, and on the increasing of the number of natural stones modified by man to make them look more beautiful. The Gemological Institute of America (Gia), has even developed a 3D software to mask false. Does it work?
A. It is one more tool, but alone is not enough. The job of the gemologist is to identify the authenticity of the stone with a suitable instrumentation. In addition, there is a price list of the maximum for each of the 4 C, but the precise value is determined by supply and demand. Traders can even evaluate the stone without even seeing her, precisely because the certificate is authentic. Things however, is terribly complicated with colored stones: no certifying agency in the world is able to identify parameters in a serious manner that may suggest the value of an emerald, a ruby and a sapphire. And for precious stones is even worse.
Q. It is said that the origin of the gems will determine the quality. It is true that the Burmese rubies are the most beautiful, as well as Colombian emeralds need to be?
A. It is a simplification: it is known that a Burmese ruby usually has the characteristics of exceptional color because it is bright red, shiny, without saturation of dark tone or purple, almost the shade of the Ferrari cars to be understood. This does not mean that similar stones can not be found even in deposits of other countries, but they are certainly rarer. For example, those thai have excellent transparency, but also a purplish tinge, or a very small saturation blue. The same applies to emeralds: some exemplar, magnificent for color and transparency, the typical characteristics of beryl Colombians, were discovered in Brazil. Sapphires of Kasmhir are of a incomparable blue, but rare, while those of Ceylon are lighter but warmer tinge and, yet, those of Siam are of a very intense shade.
D. If the origin does not guarantee the quality, what about the cut?
A. The colored stones have most complicated crystal systems than diamonds, what matters is a good symmetry and uniformity color view from above, because you will never get this profile. For this reason, a cut not perfectly centered is acceptable in emeralds, rubies and sapphires. On the contrary, it is unacceptable in a diamond.
Q. And it always comes back to cutting …
A. Make the most of both the weight and the color of the gem depends on the skill of the cutter: Australian sapphires are very dark with a greenish overtones and therefore unloved, they are usually sliced thin enough to avoid accentuating the gloom. Instead, those from Ceylon with very nice shades, but not so intense, have a much larger pavilion to enhance the color.
Q. But then the criterion of choice for these stones is the color?
A. Yes, it must be as pure as possible, reflect the idea of green or red or blue we have. Obviously, I do not see inclusions with the naked eye, maybe you can help me with a diopter glasses or two, because imperfections will lower the value. And if you happen to want to do some shopping while traveling, before you buy a stone better go before a certifying agency of the place.
Q. What are the most common counterfeits and the most economically harmful? We often hear about emeralds “No Oil ” as a sign of authenticity. Is also true for rubies and sapphires?
A. Of all the treatments mentioned is that most harmless and also the oldest: Plinius mentions in his writings that make for the most beautiful emeralds was enough to soak them in the oil. The micro-fractures resin impregnated: yes those who are serious. For sapphires the most resounding method is thermo-diffusion, which tinged with blue a natural corundum completely colorless and reduces the value one-tenth. The outcome? A gem from 70 euro including treatment, may also be assessed 1,200 Euros. While the roots of ruby, so named because opaque, are rubies of very low quality, that with a very sophisticated technique, receive infiltration glass. Are generally lead to increase the effect, in order to make the rubies completely transparent. So, a 4 -carat stone of the cost to trade effortlessly exceed 100 dollars, has the same appearance of one evaluated a 5 thousand dollars.
Q. So the certification agency guarantees the authenticity and origin of the product?
A. Yes, it checks whether it is natural or synthetic , in the first case, it has undergone treatment. Thanks to the inclusions, which are the traces of the rock in which the rock was formed, it is possible to trace the geographical area. Value there is a very wide gap related to trade, fashion, personal perception.