gems, corundum, simulants, ruby simulant, beads

A small, 4 mm natural corundum bead recently examined by the GIA Applied Gemology Department appeared purplish pink, a color likely attributable to a red substance found lining its drill hole. While it is common to see near-colorless corundum beads take on a pinkish hue when strung on red cord, this instance was unusual in that the color enhancement resulted from a coating applied directly inside the drill hole. As a result, accurately assessing the true color of such beads is impossible without first removing the coating.