4 C's (Definition)

4 C's (Definition)

Diamonds have four traits that determine their value: cut, color, clarity and carat. These are the Four C’s of Diamonds. You can use these traits as a guide to quality when you are shopping for diamond jewelry. 


Radiance and Brilliance

The cut of a diamond is what makes the gem sparkle. The facets and internal angles of a well-cut diamond reflect light back through the top of the diamond, which makes the jewel seem to glow. A well-cut diamond is more beautiful and more valuable than a poorly cut diamond of the same color and carat weight.

Symmetry and Polish

Two important aspects of a diamond’s cut that also add to the radiance and brilliance of the stone are symmetry and polish.

  • Symmetry is the external balance and alignment of the facets. A stone with good symmetry is more pleasing to the eye because the facets allow light to properly reflect back to the viewer.
  • Polish is the measure of smoothness when viewed under magnification. A well-polished diamond allows less of the light that passes through the body of the stone to be scattered by imperfections on the surface of the gem.

A diamond’s symmetry and polish is usually graded into one of five categories: Excellent, Very Good, Good, Fair and Poor. Diamonds with higher symmetry and polish grades will look more beautiful that diamonds with lower symmetry and polish grades.


The cut of a diamond is not the same thing as the shape. The shape of a diamond usually refers to the outline of the stone when viewed from above. The cut of a diamond refers to the facets that have been worked into the stone by a jeweler.


Diamonds come in many colors, but the most radiant and valuable diamonds are as clear as the purest water. The color of a diamond depends on its body color, brilliance and dispersion. Body color is the inherent color of the stone, while brilliance and dispersion depend on the size and cut as well as the shape of the gem.

Body color is rated on an alphabetical scale from D to Z. Diamonds with a color grade of D are colorless, while diamonds rated Z are a bright yellow.

  • Colorless: D, E and F. The rarest and most expensive diamonds. The difference in price between each grade is significant, yet to the untrained eye there is very little difference in appearance.
  • Near Colorless: G through J. The H and I color grade diamonds are great values because they approach the purity of the more expensive colorless diamonds but cost much less.
  • Faint Yellow: K, L and M. These grades begin to show a slight yellow tint to the naked eye. Certain shapes—such as the Princess shape—can deepen this color.
  • Very Light Yellow: N through R. The faint yellow tint begins to darken and become more prominent in diamonds of these color grades. Smaller diamonds will appear less yellow than larger diamonds of the same color grade.
  • Light Yellow: S through Z. These diamonds are a translucent gold in color, and in their own way, very beautiful.


The clarity of a diamond is the third of the Four C’s. Clarity is a measure of the diamond’s freedom from external marks or internal flaws. Internal flaws, known as inclusions, may present themselves as tiny white points, dark dots or feathery cracks within the body of the gem.

Clarity is determined by the number, placement and size of any inclusions visible from the top face of the diamond. The diamond is viewed with a 10x power microscope and rated by the standard GIA scale.

An F1 diamond is flawless, while IF diamonds have only minor surface blemishes visible under magnification. If a diamond has small, difficult to see inclusions, the stone will merit a VVS1, VVS2, VS1 or VS2 rating. SI1 and SI2 diamonds have inclusions that are easy to spot under magnification, while diamonds rated I1, I2 or I3 have inclusions that are noticeable by the naked eye.

A diamond’s flaws are as unique as a fingerprint, and if you register your diamond, the flaws and inclusions are kept on file as well.


Weights and Measures

The fourth C of diamonds is carat weight. Diamonds are priced in part by their weight. Although the other C’s greatly influence the final beauty and price of a particular stone, weight does play a part in setting the price of a diamond.

  • Diamonds are weighed by carats. Each carat is equal to 200 milligrams. Carats are divided into smaller units called points. There are 100 points in each carat.
  • Different cuts will change the size of a stone. If a diamond has a shallow cut, the top face can be bigger than the top face of a diamond of the same weight but with a deeper cut. In other words, the shallow cut diamond will look bigger, even though it weighs the same.
  • Jewelry with more than one stone uses total carat weight. Total carat weight (TW) is the combined weights of all the gems used on a piece of jewelry.

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