'Carbon spots’ is a term inaccurately used by some people in the jewellery industry to describe the appearance of certain inclusions in a diamond. The term refers to included crystals that have a dark appearance, rather than a white or transparent appearance, when viewed under a microscope. In most cases, these dark inclusions are only visible through a microscope, and do not affect the brilliance of the diamond. Nonetheless these black spots are highly undesirable imperfections as they can be spotted more easily than other inclusions.