Refers to the presence of inclusions in a diamond. 

The clarity or purity of a diamond is determined according to the effect that inclusions and marks have on the appearance of the stone when viewed face up at 10x magnification. Inclusions are natural identifying characteristics such as minerals or fractures, appearing while diamonds are formed in the earth. They may look like tiny crystals, clouds or feathers. The position of inclusions can affect the value of a diamond.

Inclusions are ranked on a scale of perfection ranging from Fl (Flawless – no internal or external inclusions visible under 10x magnification) to P (Pique) or I (Included) inclusions visible with the naked eye. If the inclusions are not visible to the naked eye, the diamond is deemed ‘eye clean’.

The position of inclusions is important in choosing a diamond. Some inclusions at or near the edge, can be hidden by a mount and therefore have a lesser effect on the beauty of a diamond. An inclusion in the middle or top of a diamond could impact the dispersion of light, sometimes making the diamond less brilliant.