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How did the 5Cs of Diamond Quality Come to Be?

Because diamonds are so valuable, it’s essential for industry professionals to have a universal grading system when comparing diamond quality. In the mid-twentieth century, GIA developed the International Diamond Grading System™ and the 5Cs as a way to objectively compare and evaluate diamonds. The Five Cs of diamond quality will give you a multitude of information about a diamond’s characteristics and value, but they can’t begin to describe one elusive quality – beauty. To do that, you’ll need to experience the diamond with your own eyes.

  • Diamond Cut Tab
  • Diamond Color Tab
  • Diamond Clarity Tab
  • Diamond Carat-Weight Tab
  • Diamond Certificate Tab
Diamond Cut

A well cut diamond is the work of a master diamond cutter. When cut properly, the diamond is better able to handle light, creating more scintillation and sparkle. In a properly cut diamond, light is reflected from one facet to another and then dispersed through the top of the stone. If the cut of the diamond is too deep, some light escapes through the opposite side of the pavilion. If the cut is too shallow, light escapes through the pavilion before it can be reflected.

Diamonds are valued by how closely they approach colorlessness – the less color, the higher the value. Most diamonds found in jewelry stores run from colorless to near-colorless with slight hints of yellow or brown. The only exceptions are the fancy-color diamonds that lie outside of this range.

Diamond Color

GIA's diamond color-grading scale is the industry’s most widely accepted grading system. The scale begins with the letter D, representing colorless, and continues, with increasing presence of color, to the letter Z. Diamonds are color-graded by comparing them to stones of known color under controlled lighting and precise viewing conditions. Many of these color distinctions are so subtle that they are invisible to the untrained eye. But these slight color differences make a very big difference in diamond quality and price.

The GIA Clarity Scale contains 11 grades, with most readily available diamonds falling into the VS or SI categories. In determining a clarity grade, GIA considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10x magnification.

Diamond Clarity
  • Flawless(FL) - No inclusions or blemishes are visible to a skilled grader using 10x magnification.
  • Internally Flawless(IL) - No inclusions and only minor blemishes are visible to a skilled grader using 10× magnification.
  • Very, Very Slightly Included (VVS1 and VVS2 - Inclusions are difficult for a skilled grader to see under 10× magnification.
  • Very Slightly Included (VS1 and VS2) - Inclusions are clearly visible under 10× magnification but can be characterized as minor
  • Slightly Included (SI1 and SI2) - Inclusions are noticeable to a skilled grader using 10× magnification.
  • Imperfect (I1, I2, and I3) - Inclusions are obvious under 10× magnification and may affect transparency and brilliance.

Diamonds and other gemstones are weighed using metric carats with one carat weighing about the same as a small paper clip, or 0.2 grams. Just as a dollar is divided into 100 pennies, a carat is divided into 100 points which means that a diamond of 50 points weighs 0.50 carats. But two diamonds of equal weight can have very different values depending on the other three characteristics of a diamond’s 4Cs: clarity, color, and cut. The majority of diamonds used in fine jewelry weigh one carat or less.

Diamond Carat-Weight

Because even a fraction of a carat can represent a considerable difference in cost when purchasing diamonds, exact precision is crucial. In the diamond industry, weight is measured to a thousandth of a carat and rounded to the nearest hundredth. Each hundredth is called a point (a 0.25 ct. diamond would be called a “twenty-five pointer”). Diamond weights greater than one carat are expressed in carats and decimals. (For instance, a 1.08 ct. stone would be described as “one point oh eight carats,” or “one oh eight.”)

E.G.L. Symbol G.I.A. Symbol

Your new diamond should be accompanied by an independent diamond certificate. This certificate ensures that your diamond is graded accurately. There are two diamond grading laboratories that are respected worldwide. The G.I.A. (Gemological Institute of America) and the E.G.L. (European Gem Laboratory). No other gem lab has the same integrity or trust. At Seymour Jewelers, most all of our .75 and larger diamonds are accompanied with a certificate issued by one of the above named laboratories.