Diamond - Valuation and 4Cs « BACK
Diamonds are mostly used for jewellery & industrial purpose etc. The dispersion of white light into spectral colors is the primary gemological characteristic of diamonds. Gemologists have developed methods of grading diamonds and other gemstones based on the characteristics most important to their value as a gem. Four characteristics known informally as the four Cs are now commonly used as the basic descriptors of diamonds - Clarity, cut, carat & colour.
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 2 carats (400 mg), VS1 clarity, E color, excellent cut princess 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 also influence the value and appearance of a gem diamond. These include physical characteristics such as the presence of fluorescence as well as the diamond's source and which gemological institute evaluated the diamond. Cleanliness also dramatically affects a diamond's beauty.
The gemological associations which grade and provide reports, (informally referred to by the term certificate or cert, which is a misnomer for many grading reports) 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. These 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.
- Diamond High Council (HRD) Official certification laboratory of the Belgian diamond industry, located in Antwerp.
- IDI - Indian Diamond Institute certificate, located in surat.
- IGI - International Gemology Institute