This relates to the marks of non-crystallised carbon called ‘inclusions’ found within the diamond.
Inclusions vary from flawless (FL) to imperfect (I3) with a number of grades in between the two extremes. Flawless diamonds are exceedingly rare and are best suited to diamonds that have a colourless grade (typically D-F range). A clarity grade of I3 which means that the diamond has inclusions which may be visible to the naked eye are best suited to lower colour grades as the inclusions won’t be as evident.
The clarity grade is determined by several factors including:
- The size of inclusions.
- How many inclusions.
- The positioning of the inclusions – inclusions found under the table affects clarity grade more so than inclusions found under the side facets.
- The visibility of the inclusions – the more visible the inclusions to the naked eye the less favourable the grade will be.