The quality of a diamond that has been faceted into a gem is primarily determined by four factors: color, cut, clarity, and carat weight. A standardized method of assessing diamond quality was developed in the 1950s by the Gemological Institute of America and is known as “The 4Cs of Diamond Quality” [5].
Color: Most gem-quality diamonds range from colorless to slightly yellow, brown, or gray. The most highly regarded and valuable diamonds are those that are completely colorless. These are the ones sold for the highest prices. However, another category of diamond gemstone is increasing in popularity. These are colored diamonds, which occur in a variety of hues including red, pink, yellow, orange, purple, blue, green and brown.
| Fancy Color Diamonds An article about the popularity of colored diamonds and how they obtain their wonderful colors. |
The value of colored diamonds is based upon the intensity, purity and quality of their color. Those with a saturated, vivid color are called “fancy-color diamonds” or “fancies”. On average, only one diamond in 10,000 has a color that earns the “fancy” designation. This rarity makes fancy-color diamonds extremely valuable. Some of them have sold at auction for over one million dollars per carat. They are some of the world’s most valuable and spectacular diamonds.
Clarity: The ideal diamond is free from fractures and inclusions (particles of foreign material within the gem). These detract from the appearance of the gem and interfere with the passage of light. When present in large numbers, dark colors, obvious positions or sizes then will significantly degrade the appearance of a cut gem and lower its value. They can also reduce the strength of the stone.
Cut: The quality of design and craftsmanship used in cutting a diamond is what determines its appearance. The angles to which the facets are cut, the proportions of the design, and the quality of the polishing are what determine its face-up appearance, brilliance, scintillation, pattern, and fire. Ideal stones are perfectly polished to be highly reflective and emit a maximum amount of fire. Corresponding faceted faces are equal in size and identical in shape. And, the edges of each faceted face meet perfectly with each of its neighbors.
Carat: Diamonds are sold by the carat (a unit of weight equal to 1/5th of a gram or 1/142nd of an ounce). Small diamonds usually cost less per carat than larger stones of equal quality. This is because very small stones are very common and large stones are exceptionally rare.
