Inclusions are ranked on a scale of perfection called clarity, which means that the fewer inclusions a diamond has, then the greater the clarity and thus making it more valuable. The clarity scale is a reminder that it is fairly common for diamonds to have natural flaws and they are rarely perfect. These are known as nature’s ‘fingerprints’ or ‘birthmarks and they can look like tiny crystals, clouds or feathers. The beauty of a diamond will not be greatly affected by inclusions as they can be hidden by the setting or the mount. There are two main bodies that set these scales, the GIA (Gemmological Institute of America) and the CIBJO (International Confederation of Jewellery Silverware and Diamonds)

At Ernest Jones we use the International Grading Scale developed by CIBJO, which is the oldest representative organisation in the jewellery industry. CIBJO measures the visibility of inclusions using a single lens magnifying glass called a loupe.

Round brilliant cut diamonds

The CIBJO scale ranks diamonds from Loupe Clean through to P (Piqué - French for picked): Loupe Clean diamonds are flawless or internally flawless and very rare and valuable. Diamonds that have very, very slight inclusions, are graded VVS1-VVS2 and, even with a loupe, the inclusions can be difficult to see.

Diamonds that are very slightly included are graded as VS1-VS2. Diamonds that are graded S1-S2 feature only slight inclusions which may or may not be visible to the naked eye. Any diamond that has inclusions that is visible to the naked eye, are P1-P3 although P1 will have fewer inclusions than P3.