4C International International Diamond Grading System


One carat is equivalent to 200 mg. One carat is divided into 100 parts (hundred).

Diamond is a unique mineral stone. It is a stone of extraordinary hardness. After cutting it fabulously turns into a magnificent diamond, the famous light game provides 57 faces. The weight of the diamond is calculated in carats. 1 carat is 0.2 grams. Diamonds up to 0.29 carats are considered small, from 0.3 to 0.99 card – average. A diamond weighing more than 1 card is already a large diamond. Diamonds weighing more than 15 carats are extremely rare, and the largest and rarest diamonds have their own history, legend, and even their name.

Carat is a unit of measurement adopted to determine weight. The word “karat” comes from the name of the seed of Ceratonia, with which people in ancient times tested the scales. Ceratonia seeds are so small and indistinguishable from each other that even the most modern technology is not able to measure the difference in weight of two seeds.

The mass of diamonds is measured on special karat scales, and approximately it can be determined by the stone’s diameter.



Determines the presence of internal inclusions in the diamond – natural characteristics of natural minerals. Inclusions are rated on the appropriate purity scale from 1 (clean) to 12 (with inclusions).

Purity is another parameter of the quality of diamonds and is expressed in the presence or absence of inclusions in the stone structure. Simultaneously, the inclusions can be both internal and superficial, from which you can get rid of with resurfacing. Internal inclusions are crystalline (mineral) or other inclusions, structural non-homogeneity, voids, and cracks deep in the diamond or traceable from its surface. External inclusions are irregularities in planes and lines of their intersection, heterogeneity of structure, colour or transparency, which are observed only on the diamond’s surface, for stones up to 0.30 carats – the maximum scale of quality – 9. For stones from 0.30 to 5.99 carats – the maximum quality scale is 12.

The lower the colour and frequency, the better the characteristics of the stone. When assessing the impact of inclusions on cleanliness, their size, nature, number, location, brightness and colour are considered. To determine the number and size of inclusions usually use a 10-fold magnifying glass, a special microscope and a GIA evaluation system.



Diamonds are classified on a colour scale that starts with 1 (colourless) and ends with 9 (coloured).

When talking about a diamond’s colour, gemologists usually mean the presence or absence of colour in a “white” diamond. The colour directly depends on the chemical composition of the diamond and does not change over time. Because a diamond is devoid of colour, like glass, it lets more light through itself than a coloured stone. Colourless diamonds sparkle more and play with light reflections. The colourless the “white” diamond, the higher its value.

There are a group of traditional-coloured diamonds (or Cape) and fancy flower diamonds. The first group includes colourless diamonds and the entire scale of yellow shades. And the most valuable is considered the so-called “diamonds of pure water”, that is, colourless, and the least valuable is considered unclear grey, yellow and brown. Exceptionally rare fantasy (red, green, pink, blue) and black diamonds are rare, and their value exceeds the value of “white” diamonds.



Determines the angles, proportions and shape of the diamond. There are eight main forms of diamond cut: Marquis, Round, Princess, Heart, Oval, Radiant, Emerald, Pear.

In the assessment of cutting the main principle is not its shape (round, princess, heart, emerald, oval, marquise), but the quality of performance. The light depends on how geometrically accurate and proportionately the diamond is faced.

Cutting is the processing of gemstones to give them the perfect shape and maximise their play and brilliance. In 1919, the mathematician M. Tolkovskiy calculated the proportions of the diamond cut, in which the light entering the stone through the platform, fully reflected from the faces of the pavilion by the law of full internal reflection and goes back, creating a strong shine and “game” (for the original form was taken round diamond with 57 faces). At such proportions, the diamond does not pass light through, as opposed to imitations.

This diamond has 57 flat faces and consists of three main parts. The middle part of the diamond (rudist) is a belt covering the largest section of the diamond’s circumference and dividing it into the upper and lower part. The top of the diamond is called a crown. The lower part is called a pavilion. The stone acquires the so-called sparkle – not abstract value, but a genuine indicator of the cut’s quality.

In the store “Golden Age” you can buy earrings with diamonds of all types of cut, as well as rings and pendants for all tastes.


Diamond (from the French Brillant – brilliant) – a diamond, which through processing is given a special shape, the so-called diamond cut, which reveals the stone’s optical properties as much as possible.

Know More on: 4Cs of Diamond Quality by GIA | Learn about Diamond Buying | What are the Diamond 4Cs

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