Diamond

Cut diamond is called a diamond.

Before we describe the basic method of distinguishing diamonds, it will be useful to list the criteria for their evaluation. Unlike other stones, diamonds valued most for the lack of color. However, only some of them are actually completely colorless, others have a slight yellow or brown tint. Colorless diamonds are called "white", but there is for white graduation.

The color of the diamond is usually estimated in comparison with a set of stone-samples. Most respected organization conducting such assessments, it is the American Gemological Institute (GIA); graduation in alphabetical order, he proposed, has spread around the world, evaluation «D» is given the best white or colorless stones, followed by the remaining letters until «Z» after which the stones have been quite pronounced yellow tint and are regarded as "colored." By category «D», «E» and «F» are colorless or "white" diamonds, and the difference between them is almost impossible to see with the naked eye, even upon closer inspection.

However, despite the fact that they are almost indistinguishable visually, these stones vary greatly in price. For example, the brilliant cut stone with a color category «D» 5 carat weight without internal cracks worth five thousand dollars per carat (U.S. - international currency in which diamonds are evaluated) rock category "E" of the same weight and purity will cost about 70% This price per carat category «F» - 50%, and the category of «L»-only 17%. Certainly, buyers seek to acquire the best stones, even for big money.

Set free from defects in the research process stone at tenfold magnification. Stone, in which such an increase cracks are found, is considered "internal integrity» (IF). The presence of tiny cracks means lower category WS, grade 1 or 2. If the crack is a little more rock is classified as VS, grade 1 or 2. The next category - SI, when the crack is visible to the naked eye, although it is very small. Further stones recognized "defective» (I). In this case, the crack is so pronounced that affect the brilliance of the stone. Damage to the surface, even a small, also means that the stone does not fall into the category of IF, though the certificate may state that he is "potentially integrity", if it repeatedly sanded, although it will be a short weight loss.

As is the case with color defects strongly affects the value of the stone: we recall the same example with brilliant cut stone weighing 5 carats and color category «D» - without cracking it will cost five thousand dollars per carat for any cracks category WSI it will be 70% of the price per carat, and in the presence of cracks category SI - 32%.

The cut is also an important factor in evaluation of diamonds: classic rock bulk diamond cut XIX century can cost 25% less than the modern rock in a good treatment. "Fire" is the best stone is visible, if brilliant cut is achieved by "total internal reflection", in which the lower edge of stone acts like a mirror, reflecting the light coming into the stone at each other and throwing it back, already overwhelmed by all the colors of the rainbow. At the beginning of XX century, jewelers began to realize that this effect is achieved only in strict compliance with the proportions of the diamond cutting and at certain angles between faces. Unfortunately, while much of the lost weight uncut diamonds, and as many old stones were re-cut, they have lost some of its value. In recent years, however, the newly increased interest in ancient rocks cut "roll", which experts valued for their uniqueness and beauty, as well as rare. More difficult to assess facets fancy stones, such as emerald, diamond cut "pear" (an archaic name - "pandelok") or "Marquis". In this case, the same weight proportions of stones can vary greatly, in addition, the price affects the quality of treatment. The most expensive are the stones, the cut of which is recognized as the "most suitable" or "exemplary."

Fancy cut influenced fashion. For stones weighing more than 20 carats of cut "emerald", "Marquis" or "pear" is preferable to the classic diamond and if give brilliant cut stone is 40 carats, it will be virtually impossible to insert into the ring, but if you choose the form of the "Emerald", it will just gorgeous. For stones less than 10 carat brilliant cut is more appropriate than fantasy.

Finally, consider the weight of the stone: diamond weighing 0.99 carats will cost much less than diamond weighing 1.10 carats stone weighing exactly 1 carat is much more difficult to sell, because even a small sanding edges to eliminate chafing, arising during socks, will lead to the weight of the stone will be less than 1 carat. Price per carat for a 2 carat stone will be higher than that of a 1 carat stone with the same color and clarity, the same for a 3 carat stone and so on. With a weight of over 10 carats rarity of such a stone will greatly increase its value. Therefore, when evaluating diamonds have to balance between the four main categories: color, clarity, cut and weight.

In nature there are diamonds of different colors. Most often, these shades of yellow and brown. The classification includes "colorless" and "almost colorless" stones. Depending on the degree of color stones can be "with a faint color", "with a very light color," "painting with light" or "color", according to the American Gemological Institute of gradation (GIA). Considered the least valuable colored diamonds brown color, which is also called "cognac" or "cinnamon", although their cost makes adjustments fashion - because they look very attractive. They are followed by yellow colored diamonds, the color "canary", the most popular stone colors "yellow daffodils". Blue and pink diamonds are extremely rare, so even weak expression of color are very expensive. Ideally, the blue diamonds have to be completely devoid of gray shades, and pink - brown. Until recently in Australia from Argyle diamond cores extracted in small amounts beautiful stones deep, pink, or even purple, despite the fact that their weight rarely exceeded 1 carat, for it offered a huge price.

The most rare are the green and red diamonds. The lucky winner of this stone can ask him almost any price: the emergence of the market produces a sensation. Recently, the highest price paid at auction for a red diamond weighing 0.95 carats - $ 880,000 ($ 926.315 per carat), which is 100 times more than the price of the best colorless diamond of the same size.

Some collectors collect only colored diamonds and have sufficient financial resources to acquire these rare examples of the treasures of the earth.

At the beginning of XX century, the discovery was made: diamonds, burned for some time with the salts of radium, get green. Unfortunately, after this procedure, radioactive stones were long, but walked the terrible rumors about how to die from skin cancer their hapless owners. Over time, this process has been enhanced and treated diamonds in nuclear reactors, making them different shades, but no residual radiation. To establish whether an artificially colored diamond, require sophisticated research that can only be done in the laboratory. Therefore, no colored diamonds are not put up for sale without a certificate of authority gemological laboratory, confirming the nature of natural color.