Which of the following describes a "color center" defect?

A "color center" defect refers to a small defect within a gemstone's atomic structure that is capable of absorbing specific wavelengths of light, which subsequently alters the perceived color of the stone. This phenomenon occurs when there is a vacancy in the crystal lattice or when an atom within the lattice is displaced. This defect results in the gemstone exhibiting different colors, which can be a natural occurrence or induced by treatments such as radiation.

Understanding color centers is significant in gemology, as they play a crucial role in defining the color characteristics of many colored gemstones. For example, in some minerals, color centers can cause the stone to appear blue or green when it absorbs certain light wavelengths. Knowledge of these defects helps gemologists assess the authenticity and natural characteristics of gemstones, as well as predict how the stone will respond to various light sources.