An interesting piece of akoya pearl trivia is that the akoya oyster is the smallest commercially farmed, pearl-producing oyster. An average akoya pearl is only 7 mm, while an average South Sea pearl is in the 12 mm range. Akoya pearls are currently being harvested in sizes from as small as 1 mm up to the very rare 10-11 mm.
Akoya pearls are inherently round, although every harvest produces a percentage of baroque and keshi pearls, which tend to have the bright luster and shine common to the akoya, but a shape and look reminiscent of a freshwater or baroque South Sea. Akoya pearls, unless color-treated, have neutral colors and overtones. Most pearls are white to grey, with pink, green, or silver overtones. Occasionally, akoya pearls are blue with silver and pink overtones, but these colors are extremely rare. Akoya pearls are never naturally black – black akoya pearls have undergone either Cobalt-60 radiation treatment or treatment with an organic dye.