When evaluating diamonds in jewelry, it is necessary to get answers to the following questions:
1. Is it a diamond?
2. How much does a diamond weigh?
3. What is the shape of the diamond? How many faces?
4. If the diamond is cut to its shape?
5. What is the grade of diamond clarity, and for some classification systems, it is defined?
6. What is the diamond's class color, and what classification system is it defined?
7. How to decipher the characteristics of the diamond in the label jewelry?
8. How much really is this diamond?
9. Is there a certificate attached to the stone with its characteristics? How to read this certificate?
10. Has this diamond been refined?
The value of any diamond is determined by four main parameters: weight in carats, cut quality, defect, color. Each of these parameters is evaluated by quantitative values, the total expression of which means the insertion value. According to the price lists, you can set the price of a faceted insert depending on the quantitative characteristics of its quality. The objectivity of the assessment is achieved by the fact that it is carried out by the agreed and generally accepted rules in international practice for determining each of the listed characteristics. There are international standards for the evaluation of diamonds.
The prices set in this way are not constant over time. They fluctuate depending on market conditions.
The weight of the diamond is estimated in carats. By weight, diamonds of all shapes are divided into three groups: small (up to 0.29 carats), medium (from 0.30 to 0.99 carats), large (from 1.00 carats, and more).
With a weight of over 10 carats, the stone's rarity significantly raises its price. A 0.99-carat diamond will cost much less than a 1.10-carat diamond. The price per carat of a 2-carat stone will be higher than that of a 1-carat stone, with the same color and purity, a 3-carat stone is higher than a 2-carat stone, etc.
The exact weight of the determined diamond can be given if the diamond is not mounted in the frame. About fixed stones, jewelers and gemologists often measure the diameter and height and then use calculations to approximate its weight. If you have any doubts about the correctness of the importance of the diamond indicated in the label, do not be lazy to go to the jeweler so that he loosens the stone and weighs it. Then you will know exactly the weight of your stone.
The classic shape of a diamond cut is considered a round shape. Usually, a faceted round diamond has 57 facets. But there are facets with more elements than 57. These are particular types of cutting. For example, the cut "Royal" has 86 facets, "Majestic" - 102 facets.
Traditionally, "princess", "emerald", "pear", "oval", "heart" are considered popular fantasy forms of cutting. It must be remembered that fantasy stones are influenced by fashion.
The cut and proportionality of the "make" diamond are significant. They affect the play (rainbow flashes coming from the stone) and the brilliance (liveliness, sparkle) of the stone. Good cutting and achieving the required proportions require a lot of experience. In addition, when perfect proportions are performed during the cutting process, the initial weight of the rough diamond is lost. That is the percentage of irretrievable losses increases. Therefore, a well-cut diamond is much more expensive than a stone with poor processing.
In Russia, the requirements for manufacturing round diamonds of simple and full-cut are determined by special technical conditions. Accordingly, the diamond's quality is checked to determine the proportions, symmetry, and quality of the surface treatment of the diamond.
Defects in diamond processing include deviations from the correct proportions, extra facets, chips, and scratches on diamonds.
Only some of the mined diamonds are really entirely colorless. The rest have a slightly yellowish or brownish tint. Colorless diamonds are called white, but there is a gradation for them. The relative absence of color or the presence of shades or natural coloring in a diamond is usually evaluated compared to a set of sample stones.
Color group – professionally defined location of the diamond on the color classification scale.
The diamond color is evaluated by experienced specialists by comparing the gemstone with reference stones under special lighting.
Diamonds of simplified cut and very small, depending on the color and intensity of coloring, are classified into color groups according to the Russian cipher: colorless - 1; with a slight shade of yellowness and with a subtle shade of yellow, green, aquamarine, and gray, as well as with a bit of brown tint – 2; with a clearly visible yellow pigment, yellow and with a slight brown shade – 3; brown – 4.
Classic cut diamonds weighing up to 0.29 carats have the following characteristics: colorless – 1; with a slight shade - 2; with a slightly yellowish, aquamarine, green, gray and with a somewhat perceptible brown shade – 3; with a clearly visible yellow, lemon, green, aquamarine, gray and with a slightly detectable brown shade - 4; yellow – with yellow, green, lemon color throughout the diamond, as well as yellow with a slight brown or marsh shade - 5; with a visible brown tint and gray – 6, brown and brown-yellow; and black - 7.
The scale of the color groups of medium and large diamonds: colorless higher, as well as with a shade of blue - 1; colorless - 2; with a subtle shade - 3; with a slight shade of yellow – 4; with a slightly yellowish, greenish, aquamarine, purple and gray tint, as well as with a small brown stain – 5; with a visible yellow, green, aquamarine and gray paint – 6; with a visible brown tint - 6-1; with a clearly visible yellow, green, lemon, aquamarine and gray shades – 7; very weakly colored yellow -8-1; weakly colored yellow - 8-2; lightly colored yellow - 8-3; light yellow - 8-4; yellow - 8-5; lightly colored brown -9-1; lightly colored brown - 9-2; brown - 9-3; dark brown - 9 - 4.
Diamonds of unique colors (blue, pink, emerald green, and other rare colors) belong to the first group.
The international market uses several color classification systems for diamonds. Below are the terms used to denote the color of one of the oldest and most popular companies among the cutters of Belgium and the Netherlands:
Jager - colorless (bluish);
Rive r- extremely transparent, colorless;
Top Wesselton - colorless, less transparent;
Wesselton - with a very, very small shade of pale yellow;
Top Crystal - with a very slight shade of pale yellow;
Crystal - with a slight shade of pale yellow;
Top Cape-with a pale yellowish tint visible to the naked eye;
Yellow – yellow.
In the USA and many other countries,
colorless diamonds are designated by letters of the alphabet,
starting with D, which characterizes an absolutely colorless diamond, and then up to the letter of the English alphabet Z,
after which the stones already have a sufficiently pronounced yellow hue and are considered colored.
A purity group is a professionally given assessment of the purity of a diamond. It is based on determining the classification scale's size and the number of defects.
Internal defects have a particularly significant impact on the degree of purity.
There are the following types of internal defects in a diamond:
1. Point. This is the most minor visible inclusion in the diamond. It appears as a tiny brightening white dot or a small contrasting black dot.
2. A group of points. It is formed by three to five points located close to each other.
3. Mineral inclusions. Various minerals are found in a diamond. Such inclusions are more prominent than a dot and have a shape and volume.
4. Dark inclusions. They are most often represented by sulfide minerals and are formed before or during diamond crystallization. Sometimes we talk about a colorless crystal wholly covered with a black-brown film (graphite). A carbon sulfide spot is a black-brown defect, which is probably formed under the influence of high temperature, causing the transition of diamond into graphite.
5. Cloud. This is a large group of points.
6. Splits (cracks). This is a crack in a diamond that originates on the surface or inside the stone. Splits can form while wearing the stone.
The presence of defects dramatically affects the value of the diamond. So, the presence of a small crack can reduce the cost by 30% at once.
According to the degree of internal defects, diamonds in Russia are conditionally classified into the following groups:
1 - diamonds that do not have any flaws;
2 - diamonds that have no more than one defect in the form of an insignificant dot;
3 - diamonds having no more than two defects in the form of light dots;
4 - diamonds having no more than three defects in the form of minor dots or one minor crack in the area of the rudest; 5 - diamonds having no more than five minor defects;
6 - diamonds with no more than seven defects;
7 - diamonds with flaws in the form of one significant crack, one large cloud or a sizeable dark inclusion, faintly visible to the naked eye;
8 - diamonds with significant defects visible to the naked eye.
A diamond does not have to be flawless to have a beautiful look. From the point of view of the stone's attractiveness, the most important factors are considered to be color and luster.