Mineral, which for many millennia was known to man as a diamond, but hid its true beauty until it was reincarnated. The Indians were the first to discover, and the Belgians turned it into a luxurious gem. Today, it shines with splendor in luxury jewelry, symbolizing wealth, and the excellent taste of the owner.
Diamond Physical properties
Chemically, a diamond is a pure carbon. Under conditions of elevated temperatures, vacuum, or an environment filled with inert gases, the mineral becomes graphite.
Varieties and colors
Diamonds are divided into 3 color groups:
White or colorless nuggets are considered the most popular and expensive gems. The highest quality stone is called “clear water” since the perfect gem really merges with water and is invisible in it.
Black stones were not considered precious for a long time until one designer started the fashion for this gem with the release of the first collection of jewelry with black diamonds. This variety differs from other brethren in opacity and absolute absorption of light. However, like other diamonds, black is endowed with a luster.
Fantasy stones are full of a variety of shades:
Red. Rare and one of the most expensive stones. The price of 1 carat exceeds 300 thousand rubles.
Green. The rarest, natural specimens are isolated and are in museums or private collectors. The cost of a carat of a green stone is about 250 thousand US dollars.
Blue. One of the rare varieties. The main color is complemented by shades of purple, green or gray. In many jewelry stores, a blue diamond is an artificial, radioactively irradiated stone.
Pink. The variety of such a stone is divided into another 20 distinct shades of pink. A rare nugget, found in a single out of 100 thousand ordinary diamonds. Only falls under the fantasy gem category if there is no brown tint.
Blue. A very rare gem of the highest value.
Brown. The most inexpensive of all fancy stones.
Yellow. Gem of a low price category, somewhat more expensive than brown.
Most often, fancy diamonds are called by a double name, for example, green-blue. The first component of the name is the main color, and the second is a complementary shade. When describing fancy stones, the degree of color saturation is also taken into account.
Criteria for the jewelry evaluation
There is an opinion that the main advantage is when evaluating it is the weight. But this is not the case. Experts in their field evaluate according to the global 4C system – Cut, Clarity, Carat, Color, that is, “Cut, Purity, Weight, Color”.
Cutting is the main asset of jewelry technology. Thanks to this type of stone processing, the once nondescript diamond was turned into a luxurious diamond. Correct cutting is aimed at the most positive result – to preserve a greater percentage of the weight of the stone, eliminate flaws, and emphasize dignity.
A classic brilliant-cut involves cutting 57 facets and giving the stone a round shape. This method is applicable to all pieces of 0.3 ct and above. 17 facets are applied on stones of minimum weight, and on large specimens – 74, 86, or 102. The round cut is also classified into groups A and B. The first denotes the ideal ratio of the shape of the stone and the facets, the second – the imperfection of proportions, elongation of the stone with a violation of symmetry.
The concept of clarity of a diamond includes the number and size of inclusions, as well as the degree of reflection of sunlight from the surface of the stone. The international classification includes 11 groups that determine the clarity of a diamond.
The scale of Russia is somewhat different. There is a 9-point scale for stones weighing up to 0.3 carats, and a scale of 12 points for diamonds ≥ 0.3 carats. In this case, the best gems of “pure water” are evaluated by 1 point, and stones of the lowest grade with a large number of inclusions are evaluated by 12 points.
In the category of measuring the weight of diamonds, the world and Russian systems are similar to each other – 1 carat is equal to 0.2 grams. There are three weight categories of diamonds: Large – over 1 carat.
Medium – 0.29 to 0.99 carats.
Small – up to 0.29 carats.
The weight of a stone in a piece is determined by the Tavernier formula and applies to stones weighing up to 5 carats. According to this formula, the cost of a carat is multiplied by twice the weight of the gem. A specimen weighing 10 carats is 100 times more expensive than a one-carat pebble. Experts advise paying attention to stones of 0.99 carats. Their advantage is that it is impossible to distinguish such a gem from a one-carat gem by eye. But the difference in price will please you noticeably.
According to the Australian system, the color of a diamond is determined on a scale from 1 to 9. The first group includes perfectly transparent stones. Further, in ascending order, the degree of yellowish or brownish tint is classified. The last, the 9th group, includes gems with visually pronounced shades of a different color. Group 3 to 5 are the best selling diamonds. However, the trick is that visually 3-4 and 4-5 levels cannot be distinguished, while the price is significantly different.
The international system evaluates the color gradation of diamonds and the degree of transparency using a scale from D to Z. Group D includes ideal stones without bloom. Group H includes yellowish diamonds, the color of which is visible to the naked eye. Category Z is the most recent, indicating a pronounced yellowness of specimens.