Education

The diamond is perhaps the most valuable gemstone on earth. Its history as one extends from thousands of years in the past to form the basis of current detailed methods practiced in cutting and appraising diamond.

Gemological characteristics

The 4C's are four variables that are used to calculate the value of a diamond: Carat weight, clarity, color and cut.

Most gem diamonds are traded on the wholesale market based on single values for each of the four Cs; for example knowing that a diamond is rated as 1.5 carats (300 mg), VS2 clarity, F color, excellent cut round brilliant, is enough to reasonably establish an expected price range. More detailed information from within each characteristic is used to determine actual market value for individual stones. Consumers who purchase individual diamonds are often advised to use the four Cs to pick the diamond that is "right" for them.

Other characteristics not described by the four Cs influence the value or appearance of a gem diamond. These characteristics include physical characteristics such as the presence of fluorescence, as well as data on a diamond's history including its source and which gemological institute performed evaluation services on the diamond. Cleanliness also dramatically affects a diamond's beauty.

There are three major non-profit gemological associations which grade and provide reports or certificates ("certs") on diamonds; while carat weight and cut angles are mathematically defined, the clarity and color are judged by the trained human eye and are therefore open to slight variance in interpretation. The associations are listed below.

Gemological Institute of America (GIA) was the first laboratory in America to issue modern diamond reports, and is held in high regard amongst gemologists for its consistent, conservative grading.

EGL USA is one of the world's premier independent gemological laboratories. For over 25 years it has offered the fine jewelry trade and consumers accurate, reliable gemstone identification and professional certification to validate their gemstone purchases.

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