Bruising a diamond is caused by a sharp blow to the stone’s surface. It is similar to bearding because it forces small feather-like inclusions into the diamond. Causes can vary, but most likely it was the cutter’s carelessness. In the interest of faster output, the cutter may sometimes contact the polishing wheel (scaife) with great force. Even if the cutter does not see the damage, chances are that it would not be serious enough to warrant losing additional weight to remove it. If a bruise is found on a larger, high clarity stone, it may be worthwhile to consider removing it if that would indeed raise the stone’s final value.
A bruise sometimes leaves a slight indent and/or pitting that is open to the surface. Occasionally geometric shapes occur outlining the grain (discussed earlier) which the damage has exposed on the diamond’s surface. At first glance (or by some descriptions) a bruise might seem to be a blemish, but since it travels beneath the surface of the diamond, it must be considered an inclusion.