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4 Cs - Articles

When measuring a diamond quality, 4 main factors are being considered: These are known as the "4 Cs".
The 4 Cs provide industry-wide standards to evaluate a diamond quality and therefore its value.

While clarity is assumed to be the most important factor of the 4 Cs, color and cut are actually more influential when considering a diamond's form.

While a diamond cut is 'artificially' determined by those who handle the stone (and naturally affect its carat value – according to its final form), its color and clarity are determine by nature and the forces (and time) which created the precious stone.

To learn about each of the 4 Cs, click on the menu or on each specific factor.


The first of the 4 Cs is diamond carat.

Carat is the weight unit used for all gemstones evaluation. One carat equals 0.2 grams and is divided into 100 points, in which one carat equals 100 points. Each point weighs 2 milligrams.

The word carat originates from the carob tree seeds, which were used for the weighing precious stones in ancient times due to their weight uniformity.

A diamond's carat is a measurement of its weight and not its size, and is not to be confused with Karat, used for determining the purity of gold.

A diamond's price per carat is significantly higher when it weighs over one carat.

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The second of the 4 Cs is diamond clarity.

A diamond's clarity is determined by the number, nature, position, size and color of its internal characteristics called "inclusions", and its surface features called "blemishes". These effects originate from the liquid magma (volcanic rock) within which the diamond was created.

A diamond's clarity is measured on a scale ranging from pure (flawless) to heavily included (I-3). The clarity of a diamond is graded by using 10X magnification under good lighting by an experienced grader. The final clarity grade is usually determined by how easily the inclusions and blemishes are seen by the grader.

Internal inclusions that affect a diamond's clarity include feathers (fractures that resemble feathers), clouds (internal crystals appearing like dust) or needles (inclusion that resemble tiny needles).

External blemishes include chips (damage to a diamond's facet), bruising (cause by an external impact) or knots (cause by inclusions penetrating the diamond's surface).

Dark inclusions found in white or colorless diamonds have the greatest affect on the drop of a diamond's clarity grading. Lighter inclusions in fancy colored diamonds are the cause of significant drop in its clarity grade.

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The third of the 4 Cs is diamond color.

A diamond's color is a result of varying quantities of nitrogen and other trace elements present in all diamonds, displacing the carbon atoms within the crystal’s structure.

As a principle, the ideal situation is a diamond which is completely colorless. Yet, diamonds of vivid color, called Fancy Color Diamonds, are extremely valuable.

Increasing degrees of a diamond's body color are measured on a scale ranging from no color at all (D) to deeply colored (Z). Beyond "Z" is the range where the diamond's color is vivid and rich, and is considered a fancy color diamond which is graded between light to fancy-deep or fancy-vivid.

Diamonds of known color are used as comparison stones for color grading. Grading is done by comparing the diamond to be graded against these "master stones" under either artificial or natural daylight.

A machine called the "Colorimeter" can be used for color grading but there is no substitute for the trained human eye.

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The fourth of the 4 Cs is diamond color.

A diamond's cut is the way a certain rough stone is polished in order to reveal its many facets. The intensity of brilliance and beauty embodied in the diamond are revealed through the expertise of a skilled diamond cutter, which might not be the case were the stone cut for its weight alone.

Ideal proportions, finish and symmetry of a cut are the cutter's goal, as well as the shape of the stone. The shape of a polished diamond is divided into Round Brilliant Cut, which refers to a round shape, and Fantasy Cut – which refers to any other shape.

A diamond's cut is not the same as its shape. Shape means the outward look of the diamond (such as round, radiant, oval and so on). Cut refers to the reflective qualities of the diamond and is perhaps the most important of the 4 Cs.

A diamond's proportion refers to the ratio between its width and its height. Cut quality ranges between an ideal cut to a poor cut.

The wrong proportions, meaning a poor cut, might cause the diamond to lose its brilliance, scintillation and fire and look artificial.

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