Feathers are especially hazardous when close to the girdle surface and/or brownish in color. When asking your setter to hide one of these feathers under a prong, ask him to proceed with great caution. Sometimes with a sharp blow, pressure from a cutter’s wheel or a stone setter’s push, feathers can travel making them larger in appearance.
Named after the appearance of a bird’s feathers, they can be so tiny that they will often look like scratches on the surface (sometimes referred to as hairline feathers). The larger the feather, the more likely it will affect the durability of the diamond. In selling highly imperfect stones, a dealer runs the risk of unhappy returning customers with feathers that have fallen out or opened up to the surface in their diamond. Of course when dealing with the trade, the buyer must be aware of such potential hazards or eventually he’ll run into problems.