What are clarity characteristics that are limited to the surface of a diamond known as?

Clarity characteristics that are limited to the surface of a diamond are known as blemishes. Blemishes can include things like scratches, nicks, or polishing marks that are visible on the outer surface of the diamond. These surface characteristics do not affect the internal structure of the diamond but can impact its overall appearance and value.

In contrast, inclusions refer to internal characteristics within the diamond, such as crystals, feathers, or other minerals trapped during the formation process. Marks may often be used interchangeably with blemishes but can refer to specific types of observations rather than a clear class of surface issues. Flaws generally encompass both surface blemishes and internal inclusions but are less specific in terms of location. The term "blemishes" precisely designates those surface irregularities that can serve as important factors in assessing the diamond's clarity grade.