All diamonds are beautiful, but they all have minute imperfections. This is what makes every single individual diamond stone as unique as a fingerprint. However, like colour, the level of imperfections in each diamond can differ hugely, and so clarity refers to the level of flawlessness the diamond has. Imperfections are classed as inclusions (internal flaws), which can make the diamond look cloudy, and blemishes (external marks) such as scratches. The fewer imperfections a diamond has, the more flawless it is, meaning the diamond is considered to be rarer and more valuable.
However, bear in mind that most imperfections will be invisible to the naked eye, and perfect clarity is exceedingly rare in a diamond. Assessments are carried out under a 10x magnification, and upon this examination, a diamond will be graded for clarity against an approved scale, as was the case for colour. Inclusions may affect the brilliance or sparkle of a diamond, as it is possible they can cloud the way the light hits or bounces off the diamond.
The GIA clarity grading scale almost exactly matches the one used by the IGI, which is what we at H Samuel use to grade our diamonds. The full GIA scale runs as below:
The IGI scale combines grades FL & IF, grouping them together as the very best clarity available.