All you need to know about the 4Cs

Cut

Probably the most important factor in determining a diamond’s value and beauty.

A finished diamond shows the skill of the cutter — who fashions the stone to bring out its brilliance and scintillation, making it sparkle from across the room. Technology can be used to assess the diamond’s light performance, and so the quality of its cut.

A diamond’s performance depends on the cutter’s decisions: the angles, the placement of the facets, and the skill to place those facets precisely. Once cut, bringing a diamond to its full luster takes time and careful polishing — a poor polish reduces brightness and sparkle.

The quality of the cut can raise or lower the value of a stone by 50% or more. The more precise the cut, the more captivating the diamond.

Color

Not all diamonds are colorless — they range from colorless to light yellow and even light brown.

The rarest of all are the truly colorless diamonds. Diamonds with color are known as fancy, and their grading is unique to each stone, like a fingerprint.

Determining a diamond’s color is done against comparison diamonds in a controlled environment, so the grade is measured rather than guessed.

Clarity

Another key quality to look for, and one that affects a diamond’s value.

Diamonds can have internal characteristics, known as inclusions, as well as external ones, known as blemishes. A flawless diamond — one with neither inclusions nor blemishes — is very rare. When grading clarity, a grader uses magnification and specific lighting, and assigns a grade based on the particular characteristics they see.

Carat

The unit of measurement used to determine a diamond’s weight.

One carat equals one fifth (1/5) of a gram, and is then divided into 100 points — so a “50-point” diamond is half a carat. Carat is weight, not size: two diamonds of equal carat can look quite different depending on their cut.