Diamond grading systems, GIA and Russian TU grading system. Diamond evaluation and certification systems What does the fourth purity group mean for a diamond?

Millions of representatives of the fair half of humanity dream of having a decoration with a stone, which became iconic thanks to the brilliant Marilyn. Stone evaluation systems help you choose the best option, in which, along with weight and cut, the color and clarity of the diamond are analyzed. It is the last two characteristics that make a diamond aesthetically attractive and affect the final price of the stone.

Diamond grading systems

A unified classification of the main parameters of a diamond was not in demand until the 1950s. The stone remained the privilege of a few; a simple taxonomy of Old Term color was sufficient; the question of the purity of the crystal did not arise.

However, after the film “Gentlemen Prefer Blondes” (1953) with Marilyn Monroe, where she sang a song about “a girl’s best friend,” diamonds became not just popular, but cult attributes.

Considering this circumstance, experts took up the problem closely. Ten years later, employees of the Gemological Institute of America (GIA) presented 4C. The system covers all the nuances that determine the value of a crystal: color, clarity, weight, cut.

Today, the GIA classification is the basis for determining the value of diamonds.

GIA Classification of Diamonds and Diamonds

Diamonds are assessed by national specialized institutions or certified specialists.

In Russia, all manipulations with cut diamonds are regulated by TU 117-4.2099-2002 “Diamonds. Technical requirements. Classification". The quality of the stone is assessed by several organizations, in particular, the Gemological Center of Moscow State University. The main characteristic of the Russian system is taking into account the weight and cut of the diamond.

Diamond clarity rating

Unlike synthetics, natural stones are imperfect. They always have flaws such as cracks or inclusions.

What is meant by the term “purity”

Purity is a quality that shows how many and what kind of inclusions are present in the stone (or records their absence).

Such defects can be internal (impregnations) or superficial (spots). There are coal or snow inclusions. Most often these are dark particles of magnetite or ilmenite, less often reddish garnet, brownish spinel or greenish malacolite. The degree of purity of the stone depends on their number, location and dimensions.

The final weight and level of cut of the diamonds are determined by the master, but he cannot always change the clarity. This refers to factors that spoil the appearance of a diamond, but cannot be eliminated without noticeable loss of weight or size.

The class of this characteristic shows how deeply the light will penetrate the pebble. The higher the level of purity, the more it “forces” the light to refract, reflecting on the edges and creating signature shimmers.

Diamond clarity (sometimes the term "clarity" is used) is determined using a 10x loupe - this is a worldwide practice.

There are no flaw-free diamonds. Transparent stones, devoid of internal inclusions, are considered ideal: the external ones are removed by polishing or ideally cut. However, if there are “strangers”, then the crystal was created by nature.

Russian scale

• According to the Russian method, the diamond clarity scale has a different basis - during distribution, the mass of crystals is measured and the number of faces is taken into account:
• small stones with 17 facets - six categories of purity;
• with 57 facets, not heavier than 0.299 carats – 9 categories;

with 57 facets, from 0.300 carats – 12.

Diamond clarity rating

The higher the category number, the worse the quality of the mineral. The best degree of purity is for stones of the first category in all classifications. These are minerals without fracturing, foreign fragments or other flaws. They are counted in units and cost exorbitantly.

GIA Score

	The system distributes stones into 11 classes. Importance is given to the dimensions, quantity and degree of distinguishability of internal and external inclusions. The carat and cut of the stone are not taken into account:	Designation	Class
1	Characteristic	Flawless	F
2	Ideal	Internally Flawless	IF
3	Almost ideal	Very Very Small Inclusions	VVS 1, VVS
4	Very, very small inclusions (one or two - indicated by the number)	Very Small Inclusions	VS 1, VS 2
5	Very small inclusions (one or two - indicated by the number)	Small Inclusions	SI 1, SI
6	Small inclusions	Imperfect	I 1, I 2, I

Far from perfect example

Product tags indicate data on different scales. The following table will help you avoid confusion and correctly determine cleanliness:

GIA	Russian system (cut, carat)			Description (valid options)
	Up to 0.299		From 0.300
	Kr - 17	Kr - 57	Kr - 17
Flawless	1	1	1	No defects found.
Internally Flawless	2	2	2	One or two light dots in the center or on the periphery or a stripe (acceptable).
VVS 1, VVS 2	-	3	3	A maximum of three light dots or one or two barely visible dots or lines of dark shades.
-	-	-	4	Dark dots - one or two, almost invisible, concentrated in depth, or light dots - small, up to four, any segment of the stone, a small surface crack is acceptable.
VS 1	3	4	5	A small crack or light haze in depth, up to six light dotted or striped fragments or up to three dark dotted inclusions.
VS 2	-	5	6	No more than one graphite inclusion, up to eight bubbles, stripes, light-colored dots, cracks; up to five dark dot fragments.
SI 1, SI 2	-	-	7, 7a	Graphite haze, no more than two single inclusions of graphite, up to eight small flaws in total.
SI 3	4	6	8	Many minor defects, some of which are barely visible under a magnifying glass.
I 1	-	-	9	Cracks are sometimes accompanied by inclusions or visible to the naked eye.
I 2	-	7	10	Multiple defects, transparency at least 60%.
I 3	5	8	11	Numerous flaws, transparency 30-60%.
-	6	9	12	Numerous flaws, transparency up to 30%.

The visibility of flaws with the naked eye (without a magnifying glass) depends on the size of the stone: on minerals up to 0.299 they are visible starting from purity level 6, on specimens heavier than 0.300 - from 7. These data should be taken into account when purchasing stones.

Diamond color

The principles of color evaluation of diamonds in the Russian Federation and the world are not the same. Colorless or colored (fancy) stones are also distributed differently.

There are no flaw-free diamonds. Transparent stones, devoid of internal inclusions, are considered ideal: the external ones are removed by polishing or ideally cut. However, if there are “strangers”, then the crystal was created by nature.

According to Russian standards, the color of a diamond is determined on three scales. It takes into account how many faces the stone has and what its carat weight is.

Stones with 17 facets are divided into four groups according to color:

1. white with a subtle bluish tint;
2. yellowishness is insignificant;
3. white with a visible color tint or yellow;
4. brown.

For 57-sided stones not heavier than 0.299 carats, seven groups are distinguished:

For stones with 57 facets from 0.300 carats - 9 groups:

Stones are not compared to a standard (as in GIA). When characterizing appearance, verbal descriptions are used. It is difficult for an ignorant person to understand, since even the official document operates with vague concepts: “barely noticeable”, “with a barely noticeable tint” and the like.

A classification has been developed for yellow and brown colors that is not provided by the GIA.

The higher the category number, the worse the quality of the mineral. The best degree of purity is for stones of the first category in all classifications. These are minerals without fracturing, foreign fragments or other flaws. They are counted in units and cost exorbitantly.

A special feature of the color evaluation system according to the international method is the use of two scales: for colorless and fancy specimens. There is no gradation based on weight or number of edges.

The shade is determined by comparing the sample with a diamond standard. For white crystals, the indicator depends on the letter: the gradation goes from D to Z.

D is a completely colorless pebble, yellowness begins at level K, which reaches noticeable at step Z. Specimens of category Z are conditionally yellow stones.

Colored (not white) diamonds are classified into special color groups. Their common name is “Fancy”, that is, “fantasy”. The scale is radically different from the “white” one: the darker the mineral, the more expensive it is.

Correlation of color scale indicators

White (colorless) diamonds are graded:

GIA	Russia
	up to 0.299 carats	from 0.300 carats
D	1	1
E	1	2
Flawless	2	3
G	3	4
H	3	5
I	4	6
J	4	7
K-Z	5	8 (1-5)
	6	6 (1),
	7

Color or clarity: which to choose?

This dilemma often arises when purchasing a diamond. Both factors are important; the choice is made based on specific circumstances.

• Color comes first if the jewelry is intended for a specific setting. For a white frame, a colorless diamond with visible tints is undesirable: the yellowishness will only intensify.
• Clarity is more important than color when the setting is yellow gold: it will absorb the yellowish tones of the stone. The gem will visually “whiten” and if it is of low quality, the contamination will become obvious. The diamond should look clean.

Clarity and color are the most important characteristics of a diamond. On the tag they are indicated side by side in the form of numbers: the first is a score for color, the second is for purity. For example, 3/3 is an almost transparent mineral with a maximum of two minor defects.

What to consider when buying diamonds

If funds allow, it is better to choose a specimen without visually visible defects.

For models with 57 facets, the third category is considered good clarity for a diamond; for 17-facets, the second or third category is suitable. According to GIA this means F, G and H.

The best-selling stones are those whose color and clarity correspond to levels 3/3, 4/4, 6/6. Round specimens larger than a carat with a purity of 3 - 6 are considered investment grade. They never become cheaper and their resale value decreases little.

Silver ring with diamond

The location of the defect is important. If it is on the “platform”, the shine and play of light are minimal. Small cracks or similar flaws near the edge are not important: they will be hidden by the frame of the product.

A precious gem of purity level 4 does not have the conflict of basic parameters inherent in pure stones.

If you need a decent-looking diamond, but have limited funds, it is better to purchase a large 6/6 stone. In terms of quality, it belongs to the average group, but successfully imitates a higher level. The differences are only noticeable under a 10x magnifying glass.

This is the most sought after jewelry insert in Europe.

Conclusion

For many, buying a diamond or a product with it is a single event in life for which they prepare. If it is not possible to take a knowledgeable person with you, the attached tag will help you evaluate the quality of the stone.

You need to pay attention to what scale the assessment is on, look at the numbers and letters.

Jewelers work with stones that have no defects or are barely noticeable. Microscopic cracks, inclusions or darkening should not be repulsive: they confirm the natural origin of the diamond.

Noble stones of amazing beauty today decorate a wide variety of jewelry: earrings, rings, bracelets, necklaces, tiaras... And there is hardly a girl in the world who will not be delighted with a ring with a diamond. Due to its attractiveness and high cost, jewelry with a stone of even 0.1 carats is a reason to assume that a person has serious intentions towards you. Therefore, it is not surprising that most often a 0.5 carat diamond ring is presented as an engagement gift.

What is so fascinating about these stones that for decades they have made us want to own and admire them? Today there are quite a few gems, but the diamond has not yielded its royal title to any of them. Perhaps the secret of popularity lies in the fact that one stone, say 0.12 carats, is able to contain the mysterious shimmer of many shades and attract with its dazzling shine?

Rings inlaid with other gems are undoubtedly very beautiful. Some people buy them following fashion trends, others - due to personal preferences, but only (even 0.2 carats) have such magnetism and elegance that no other gem can compare with. Diamond jewelry has long existed outside of time and fashion. They can be very modest or indecently luxurious, but, of course, a diamond ring is always a sophisticated decoration, both on the hand of a business woman and on the hand of a young girl.

What do we know about diamonds, what types are they?

A diamond is a completely unique work of nature, presented to the world with the light hand of a jeweler-cutter. Many people mistakenly believe that diamonds are exclusively colorless, but this is by no means true. There are also colored diamonds, the color of which is called fancy, this is due to the fact that the richness of their color cannot be imagined even in the wildest fantasies. So, the color group of a diamond is one of the factors influencing its value. It is believed that the most valuable stones are completely colorless ones (collectors hunt for them), but fancy ones have a certain individuality; you will remember them forever when you see them once. Let's look at the types of diamonds by color.

Table 1. Diamond color scale.

By the way, the best jewelry is dominated by colors D - K. As for color shades, yellow and brown reduce the cost of the stone. But still, out of a thousand diamonds, only one has a deep natural color, and it should be given its due. No matter how paradoxical it may be, the most expensive diamond in the world is the pink stone. Its name is “Pink Graff”, weight is 24.78 carats, price is 46.16 million dollars.

Ring with a 0.5 carat diamond. How to calculate the weight of a stone?

Carat is a unit of measurement for diamonds, (ct). In ancient times, the seeds of the Carib tree were used as a natural measure of diamonds. Of course, you are interested in the question: “how many grams are in one carat”? The carat weight is equivalent to 0.2 grams. The weight of a diamond is measured to the nearest 0.01 ct; smaller stones are considered chips. The carat scale has 100 units. The classification of diamonds by weight is as follows

Small, when the weight of the stone is less than 0.29 carats;

Medium, when the weight of the stone is from 0.3 to 0.99 carats;

Large, when the weight of the stone is more than 1 carat;

The concept of carat should not be confused with the concept of diamond size, because stones of the same mass can have different cut shapes and have completely different dimensions. As the size increases, the cost of a carat of a diamond also increases, and very rapidly, because in nature it is quite rare to find diamonds without defects and chips, which after processing will have a large weight and an impeccable appearance. The relationship between the size and weight of diamonds is shown in the diamond carat table.

Table 2. Diamond carat.

By the way, the largest diamond in the world, weighing 545.67 carats, is called the “Golden Jubilee”. Converting carats to grams is easy, it will be 109.134 grams. The stone has a yellow-brown tint and is today kept in Bangkok, namely in the Royal Palace.

What is the clarity of a diamond and how can you tell it?

The purity of a diamond is a complex concept that determines the degree of presence of external or internal defects (cracks, natural inclusions, etc.), their number and location. This parameter is very important because it indicates how easily the diamond can reflect light and how difficult it will be to cut. Let’s reveal a little secret: each buyer can independently determine or check whether the diamond’s purity parameter corresponds to the specified value by examining the stone under a 10x magnification magnifying glass. Diamond color and clarity are indicators of a diamond's attractiveness, sometimes rarity, and in all cases, value.

There is a generally accepted classification of diamonds by clarity, in which the clarity group of a diamond is designated by letters. You can see it in the following table.

Table 3. Types of diamonds by clarity.

In this case, diamonds can be presented in completely different price categories. It is very important to take into account the purity parameter, because it greatly affects the cost of the stone. By the way, conscientious manufacturers always make an appropriate mark indicating the quality of the product offered.

How many facets does a diamond have?

Cutting a stone is a grinding process, as a result of which various planes are applied to it and the stone takes on a certain shape. The applied planes are called facets or faces. Diamonds of various shapes are found in nature, but their properties (color, shine, play of light) are revealed only through cutting, which, moreover, well hides various natural imperfections.

Until the 20th century, the rose cut was considered the most fashionable form of cutting, but it has ceased to be relevant since the advent of the round “diamond cut.” In 1919, the famous mathematician Marcel Tolkowsky was able to determine the ideal shape for cutting diamonds. The scientist made a phenomenal discovery based on the law of total internal reflection. The light that hits the surface of a stone is reflected from its faces, according to the law, and comes back out. This is how the optical properties of the stone are manifested in the best possible way, creating a unique play of light. An ideal round diamond should have 57 facets. But the larger the stone, the more facets it has. If we consider diamonds less than 0.03 carats, then the number of their faces is 17, from 0.03 to 0.05 carats - 33 faces. However, quite often jewelers make even a 0.03 carat diamond with 57 facets.

There are other forms of galleys, they are usually called fantasy. Fancy cut types are also divided into two types:

wedges, in proportions and processing close to the round shape of a diamond (oval, pear, marquise, princess, heart, radiant, etc.);

stepped, when the cut is stacked in tiers (emerald, baguette, etc.)

Can you tell the difference between the same cut shapes? Yes, this is quite possible. The rule here is that the higher the quality of processing, the better its shine. Take, for example, two identical rings with a 0.5 carat diamond of the same clarity, if one stone is lighter, more brilliant and brighter, this is the merit of a good jeweler and the impeccable quality of the cut.

The main question of the buyer: how to choose a diamond ring?

Diamonds, as previously mentioned, are quite expensive stones. Since ancient times, people have lost an entire fortune for one such gem. For their sake, conspiracies, deceptions and even murders were committed. Jewelry with diamonds was given to loved ones, they were worn only by princesses and queens, they were considered a symbol of beauty, elegance and high financial status. Time can change everything, but diamonds and the attitude towards them have not changed at all. These are still luxurious stones that everyone wants to own.

The high value and rarity of diamonds raises the question of determining their quality. It often happens that it is more expensive to buy a 0.3 carat diamond than a 1 carat diamond. Why? Because the cut quality, clarity and color of the first one will be better than the other. Each of the parameters described above plays a role in determining the final cost of the product. The higher each of them, the more expensive the stone will be. Jewelry with diamonds has status and prestige also because they are used in a noble setting: platinum and gold of various shades.

If you decide to buy a diamond ring of 0.25 carats or larger, you need to be able to read what is written on the manufacturer's tag. For example, the jewelry label may have the following formula 2 Kr 57 - 0.3 G/ VVS, where

coefficient 2 means that there are 2 diamonds in the product;

Kr is a cut shape - round;

57 - the number of facets of a diamond;

0.3 - the weight of both diamonds;

G is the color of the stone (more saturated, but almost colorless);

VVS - clarity of the stone (with minor inclusions, which can only be examined with special equipment by a jeweler qualified in this field.)

It is important to understand what is offered to you in the store; be sure to read this material before purchasing. The most popular question from buyers is: “how much does one carat of diamond cost?” The answer to this is very simple - as much as you are willing to pay for it, because diamonds are very different, so everyone can choose the one that suits their taste and budget!

Diamond color is one of its most characteristic features. As we know, visible white light is a mixture of the colors of the rainbow from red to orange, yellow, yellow-green, green, blue-green and blue. Individual components of visible light are absorbed inside the diamond - this is caused either by the presence of various trace elements or by the structure of the diamond. The parts of light that are not absorbed form the visible color of the diamond. Conversely, if all components of light are absorbed evenly, the diamond appears colorless.

Diamonds of different colors

Important diamond color feature is a relatively weak color saturation. Most diamonds used in jewelry have pale color tones and shades and appear colorless to most. An untrained human eye will not be able to distinguish between diamonds adjacent to the color chart, but colored diamonds are unlikely to leave anyone indifferent.

The photograph shows 8 loose diamonds from the pavilion side. It is impossible to look at a diamond from this side when the diamond is mounted in a setting, but the difference in color is clearly visible when viewing the diamonds from the pavilion side. The first diamond on the left is colorless (color group 1), and the one on the right has a slightly noticeable tint - its color designation according to the Russian grading system 8.2. Some people like diamonds with a yellow tint over colorless ones because... Such “sun stones” have a warm shade of color. In the catalog of certified diamonds, you can choose large diamonds with a color group from 1 to 8.2 and small diamonds with a color group from 1 to 5.

Table of diamond color according to diamond classification GOST R 52913-2008* for diamonds weighing over 0.30 carats

	Diamond color
Colorless higher ones, as well as with a bluish tint
Colorless diamonds
With a subtle tint of diamonds
Diamonds with slight yellowish, lilac and gray tint, as well as slight brown tint
Diamonds with visible yellow and gray tint
Diamonds with a visible brown tint
With clearly visible yellow, lemon and gray tints, diamonds
Very lightly colored yellow diamonds
The diamonds weighing from 0.30 carats with a range of colors from 1 to 8.1 are presented.
Faintly colored yellow diamonds
Lightly colored yellow diamonds
Light yellow diamonds
Yellow Diamonds
Faintly colored brown diamonds
Lightly colored brown diamonds
Brown diamonds
Dark brown, black diamonds

Diamond color chart according to diamond classification GOST R 52913-2008* for diamonds weighing up to 0.29 carats

Characteristics of Diamond Color Groups	Diamond color
Colorless supreme, colorless diamonds
With slight tint diamonds
With a slight yellowish, lilac, gray and subtle brown tint, diamonds
IN Diamond Expert catalog of certified diamonds diamonds weighing up to 0.299 carats are presented with a range of colors from 1 to 3.
Diamonds with clearly visible yellow, lemon, gray and faint brown tints
Yellow - with yellow, lemon color throughout the diamond, as well as yellow diamonds with a slight brown tint
With visible brown tint and gray diamonds
Brown and yellow-brown, black diamonds

* Classification of diamonds by color groups is valid from 01/01/2009

The simplest way to evaluate the color of a diamond requires appropriately folded white paper, master diamonds, and a daylight source from the northern sky (northern light). Diamonds are placed on the paper in a row near the central fold, with the pad facing down, to compare the color and color shades; no shadows should be created, and the light should be diffused to eliminate reflections and shine of the diamonds that interfere with the color assessment. The gaze should be directed perpendicular to the surface of the diamond. In this position, with a brief, concentrated look, you can very quickly recognize the subtle color shades of each of the diamonds. In the process of assessing the color of a diamond, you need to change the position of the paper relative to the light source. Also, to assess the diamond’s own color, you should breathe on the stone - light color shades are most clearly visible when the plaque from the breath begins to evaporate from the surface of the diamond.

Features of diamond color assessment: fluorescence

Some diamonds have the property of fluorescence with light blue, even light green, yellow or reddish light. Diamond fluorescence is caused by intense exposure to ultraviolet rays. For most diamonds, fluorescence is so weak that it can be ignored when assessing color. In the rarest cases, fluorescence is caused by ordinary daylight enriched with ultraviolet rays.

Diamonds under ultraviolet light

The human need for jewelry goes back to ancient history. And it’s a pity that many people forget about this, and jewelry is now beginning to play a mechanical role for many. But we must not forget that diamond jewelry is very beautiful and you should not limit yourself to the need to make your image more dazzling!

Diamonds are exposed to radiation not only in nature, but also with the help of humans. As a result, they greatly change color to green, blue, yellow or pink. Radiation processing is so widespread that it is not worth even thinking about buy a diamond decent size and attractive or unusual color without a certificate from a gemological laboratory confirming the natural nature of the color. Not long ago, new methods of influencing this stone appeared, in particular the method of high pressure and temperature, with which you can change and enhance the color of diamonds belonging to a certain subgroup. Inconspicuous dark inclusions can be removed by laser drilling, but at high magnification you can usually see the marks left by the laser. And finally, sometimes flat cleats and cracks in diamonds are filled with spectacularly refracted substances, after which the stone appears more attractive to the naked eye.

The most popular and most expensive diamonds are round cut. More than 90% of all diamonds are round cut. It is round cut diamonds that have the most vibrant play of all cut shapes. This cut is the most thought out in terms of optical properties, i.e. sparkle, scintillation, which is why fancy cuts are cheaper than round ones. When creating a round cut, the yield from a diamond is significantly less than with other cuts - more than half of the rough diamond. The round cut is distinguished from all other forms primarily by the standard ornamentation of edges and proportions, the approach to assessing the quality of processing, and its higher cost.

If the proportions are strictly observed, a round diamond can reflect almost all the light that hits it. For small stones, a 17-sided cut (Kr-17) is used, and larger stones are cut into 57 facets (Kr-57). Round cut diamonds with 57 facets are divided into four groups depending on compliance with the technical parameters of symmetry, polishing and geometry

• A – ideal cutting parameters
• B – good quality parameters
• B - satisfactory cutting quality
• D – cut quality below satisfactory level

Small round diamonds with 17 facets and fancy cut stones have only two grades: “A” and “B”. Fancy cut

It can be divided into two groups

• wedge, which in their proportions are close to a round diamond (marquise, pear, oval, heart, princess, radiant, etc.)
• stepped(emerald, baguette, etc.). They have a special unique appeal and look great in jewelry.

Diamonds, like most other minerals, have natural inclusions and defects in their structure. The fewer there are, the more valuable the diamond. Absolutely transparent diamonds are practically never found in nature; we can only talk about the purity of a diamond under tenfold magnification. If no defects are found, the stone is recognized as a pure diamond. It is not a fact that at higher magnification the defects in such a stone will not be noticeable.

In order to determine the clarity of a diamond, it is necessary to determine the number and nature of defects, as well as the size and location of these defects. Diamond clarity is assessed at 10x magnification using a magnifying glass or a special microscope. In this case, the GIA and Russian assessment systems are used.

Color classification according to the Russian system and the international GIA

In accordance with the international GIA system (), color gradations are characterized by letter designations from D - colorless to Z - deep yellow. Yellow and brown stones with a color characteristic below Z are considered fancy.

The domestic scale is designated by numbers from 1 (colorless) to 9 (brown). The color scale is divided into groups, it begins with completely colorless diamonds, then there are smooth transitions with increasing yellow color saturation and ends with the last group, which has a clear yellow color. At the same time, the Russian classification takes into account the weight categories of diamonds and the number of facets.

Small round cut diamonds with 17 facets have 4 color categories, and those with 57 facets have 7 categories. Medium and large diamonds are divided into 9 color categories.

Small diamonds Kr-57

Medium and large diamonds Kr-57

Purity classification according to the GIA system

The system distributes stones into 11 classes. Importance is given to the dimensions, quantity and degree of distinguishability of internal and external inclusions. The carat and cut of the stone are not taken into account:	Cleanliness group	Characteristics of purity groups
Flawless	Flawless (flawlessly clean)	When observed through a 10x magnifying glass, no visible defects are observed.
Internally Flawless	INTERNALLY FLAWLESS (pure)	At 10x magnification, internal imperfections are not noticeable, only minor surface defects are detected, which can be easily removed with re-polishing.
VVS1 VVS2	VERY, VERY SMALL INCLUSIONS	At 10x magnification, the smallest dots in VVS1 grade stones are extremely difficult to see through the platform and can only be detected when viewing the stone through the pavilion. This class also includes diamonds with very small and shallow inclusions, which are removed by repeated polishing. In VVS2 class stones, the smallest inclusions can be detected with great difficulty when viewing the stone through the platform.
VS1 VS2	VERY SMALL INCLUSIONS	At 10x magnification, minor inclusions in the form of very small feathers and clouds are difficult to detect in VS1 grade stones and somewhat easier to detect in VS2 grade diamonds.
SI1 SI2	SMALL INCLUSIONS	Small noticeable inclusions At 10x magnification, noticeable inclusions in SI1 stones are easily detected and very easily in SI2 stones; Sometimes small inclusions in SI2 stones are visible to the naked eye.
I1 I2 I3	IMPERFECT (there are explicit inclusions)	In stones of these classes, obvious inclusions are visible at 10x magnification and even with the naked eye through the platform. These inclusions affect the durability of the stone or are so numerous that they seriously affect the clarity and brilliance of the diamond.

Russian purity classification system

Characteristics of purity groups	up to 0.29 carats	from 0.30 carats and more
No defects observed	1	1
There are a very small number of subtle defects in the form of light dots.	2	2
There are a very small number of defects in the form of dark and light dots.	3	3
A small number of inclusions of dark and light dots and stripes are observed.	3	4
There are a number of dark and light dots, stripes, and small cracks.	4	5
A number of dark and light dots, stripes, as well as small cracks, bubbles, growth lines and graphite inclusions are observed.	5	6
There are a sufficient number of dark and light dots, stripes, as well as small cracks, bubbles, growth lines and graphite inclusions, visible to the naked eye.	5	7
There are numerous inclusions and defects visible to the naked eye.	6	8,9
Numerous inclusions and defects are clearly visible even to the naked eye.	7,8,9	10,11,12

Jewelry presented on the Russian market contains diamonds graded by both Russian and international systems. Converting values ​​from one classification to another is very simple.

Despite the apparent complexity, diamond grading is largely unified. There is a system of price lists that determine the approximate cost of stones. It is customary in the world to describe the characteristics of diamonds, taking into account four characteristics of stones: color (Color), clarity (Clarity), carat weight (Carat) and cut (Cut).

The classification of diamonds based on these characteristics is called “4C”.

Diamond color

Although diamonds are mostly colorless, some have shades of pale yellow, yellow or brown of varying intensities. Absolutely transparent, flawless diamonds are said to be “pure water.” Such stones, when they do not have any color tint, with the exception of bluish, are most highly valued. Diamonds with a faint yellowish tint are called “impure water” stones and are valued significantly less.

Canary yellow diamonds have a certain appeal. Greenish stones are also common, although a really good shade of this color is rarely found within a whole crystal. Brown stones are not uncommon, especially from South Africa. Pink stones are less common, while ruby ​​red, mauve and blue stones are rare. Stones with the last of these colors usually have a “steel” tint. Sapphire blue diamonds are extremely rare and very expensive.

A number of terms were used to describe the color of diamonds, such as "jager", "river", "wosselton" and "cape", many of these terms were derived from the names of South African mines. About half a century ago, these "old terms" were largely replaced by purely descriptive definitions, such as "bluish white", "pure white", "light yellow". However, the term "bluish-white" was considered meaningless and was not recommended for use. German jewelers used a numerical classification of colors from the first to the sixth color. To facilitate the procedure for determining the color of stones, a device was invented that made it possible to directly compare the color of diamonds with standard colors.

In Russia, color characteristics are usually denoted by numbers. Depending on the weight of the diamond, the range of the color scale varies. Thus, diamonds with 57 facets and weighing up to 0.29 carats have colors from groups 1 to 7. Diamonds of the same cut from 0.3 carats and above are divided into 9 groups according to color shades:

Group number	Decoding
Group 1	colorless higher ones, as well as with a tint of blue
Group 2	colorless
Group 3	with a subtle tint
Group 4	with a slight tint of yellowness
Group 5	with slight yellowish, greenish, aquamarine, violet and gray tints
Group 6	with visible yellow, green, aquamarine, gray and slight brown tints
Group 7	with clearly visible yellow, green, lemon, aquamarine, and gray shades
Group 8	yellow (with yellow, green, lemon color throughout the diamond)
Group 9	brown or yellow-brown

Abroad, different designations for the color of diamonds are accepted. Diamond World provides a summary table of standards for assessing the color of stones in various countries. The most common of these is the Gemological Institute of America (G.I.A.) color scale.

G.l.A.	C.I.B.J.O.	I.D.C./H.R.D.	U.K.	SCAN.D.N. (up to 0.5 carats)	SCAN.D.N. (0.5 carat and above)
D	Blanc cxeptionnel +	Exceptional white +	Finest white	Rarest white	River
E	Blanc cxeptionnel	Exceptional White
Flawless	Extra blanc +	Rare white +	Fine white	Rare white	Top Wescllon
G	Extra blanc	Rare white
H	Blanc	White	White	White	Wesselton
I	Blanc nuance	Slightly tinted white	Commercial white	Slightly tinted white	Top crystal
J			Top silver Cape		Crystal
K	Blanc legerement teinte	Tinted white	Silver Cape	Tinted white	Top Cape
L
M	Teinte	Tinted	Light Cape	Slightly yellowish	Cape
N
O			Cape	Yellowish
P
Q
R
S-Z			Dark Cape

Diamond Clarity

Almost all diamonds contain inclusions of uncrystallized carbon or small foreign crystals. Most of them are invisible to the naked eye and require multiple magnifications to identify them. The fewer such inclusions in a stone, the “purer” and more valuable the diamond. In other words, the term “clarity” is used to determine whether the diamond being purchased is free from defects. Diamonds are divided into several groups according to their purity. Diamonds are distinguished from pure, through various gradations of imperfect, to the so-called “pique”, which contain inclusions that are visible to the naked eye.

In Russia, the quality characteristics of diamonds, as well as the color characteristics, are usually denoted by numbers. Diamonds with 57 facets weighing up to 0.3 carats have a digital clarity designation from 1 to 9. Diamonds of the same cut from 0.3 carats and above are divided into 12 groups.

As with color, different countries have their own standards for grading the clarity of diamonds.

Table of international standards.

G.I.A.	C.I.B.J.O.	SCAN.D.N.
Characteristic	Characteristic	Characteristic
Internally Flawless	-	Internally Flawless
VVS1 VVS2	VVS1 VVS2	VVS1 VVS2
VS1 VS2	VS1 VS2	VS1 VS2
SI1 SI2	S.I.	SI1 SI2
I1	P1	P1
I2	P2	P2
I3	P3	P3

Diamond weight

When grading large diamonds, clarity and color are important. Small stones are valued by weight, and not by their individual qualities. In general, the weight of stones plays a major role in determining the cost of diamonds.

The unit of measurement for the mass of rough and polished diamonds is the carat. The word “carat” itself comes from the name of the seeds of the Carib tree, which in ancient times served as a natural measure of the weight of diamonds. One carat is 0.2 grams. The carat scale is divided into 100 units.

Diamonds weighing up to 0.29 carats are considered small, medium – from 0.3 to 0.99 carats and large (“solitaires”) – 1 carat or more. Diamonds weighing more than 6 carats are usually sold at auction.

Small diamonds of varying sizes, obtained either by cutting a small rough diamond or by cutting parts of a cut larger gemstone and weighing less than 0.25 carats each individually, are called melee. The term melange is used to refer to larger stones of varying sizes.

Diamonds are valued according to the so-called “Tavernier rule”: the cost of a stone is equal to the product of the square of the mass (weight) of the crystal in carats and the base price of one carat. Thus, a 2-carat diamond costs 3 times more than a one-carat diamond, and a 3-carat diamond costs 10 times more. This “progression” increases to 5 carats. A 10-carat diamond is valued at 100 times more expensive than a one-carat diamond. Diamonds over 25 carats are given their own names.

The weight of diamonds is measured to the nearest 0.01 carats. One carat is equal to 200 milligrams or 1/5 of a gram. The weight of diamonds is measured on special carat scales, and it can be approximately determined by the diameter of the stone:

• Weight 0.03 ct = diameter 2.0 mm;
• Weight 0.10 ct = diameter 3.0 mm;
• Weight 0.30 ct = diameter 4.3 mm;
• Weight 1.00 ct = diameter 6.5 mm;
• Weight 1.50 ct = diameter 7.5 mm;
• Weight 2.00 ct = diameter 8.2 mm;
• Weight 3.00 ct = diameter 9.4 mm.

Diamond cut

The most popular and most expensive round diamonds are K-57 cut. These diamonds have the most brilliant play of all cut shapes. If the proportions are strictly observed, a round diamond can reflect almost all the light that hits it.

Fancy cut shapes - marquise, princess, heart, pear and others - have a special unique appeal and look great in jewelry.

Diamond elements

Diamond top view

Bottom view of diamond

Diamond cut shapes

Diamond color

Diamonds vary in color from colorless to yellow. To correctly determine the color, a diamond is compared with standards and assigned an appropriate index on the color scale. Other colors - fancy (orange, pink, blue and others) are quite rare.

In accordance with the international G.I.A. system (Gemological Institute of America) color gradations are characterized by letter designations from D to Z, on the domestic scale - by numbers from 1 (colorless) to 9 (brown).

Diamond color scale ratio table

THAT up to 0.29 ct	1		2	3		4		5	6	7
THAT from 0.30 ct	1	2	3	4	5	6	7	8 (1-5)	6 (1), 9 (1-4)
GIA	D	E	Flawless	G	H	I	J	K-Z

Diamond Clarity

Diamonds, like most other minerals, are characterized by natural inclusions and defects.

In order to determine the clarity of a diamond, it is necessary to determine the number and nature of defects, as well as their size and location. The examination is carried out at 10x magnification using a magnifying glass or a special microscope.

Ratio of diamond clarity scales

THAT up to 0.29 ct	1	2	3		4	5			6		7	8	9
THAT from 0.30 ct	1	2	3	4	5	6	7	7a	8	9	10	11	12
GIA	Internally Flawless		VVS1	VVS2	VS1	VS2	SI1	SI2	SI3	I1	I2	I3

• 1 - clean
• 2-3, 3-4 - very small inclusions
• 5-6 - very small minor inclusions
• 7-8 - small noticeable inclusions
• 9-10, 11, 12 - inclusions visible to the naked eye

Diamond Certificate

Diamond certification is widely used throughout the world. The most famous certification centers are C.I.A. (Gemological Institute of America), E.G.L. (European Gemological Laboratory), I.G.I. (International Gemological Institute).

The certificate is issued on the basis of an independent expert assessment. The gemological laboratory that issued such a certificate guarantees the accuracy and reliability of the information contained in it.

A certificate is a kind of diamond passport, which indicates its individual characteristics: shape, size, proportions, weight, color, clarity, quality of cutting and polishing.

According to Russian legislation, all loose diamonds supplied for retail sale must be certified.