Akoya pearls, produced by small Japanese oysters, Pinctada imbricate = martensi, fucata, are implanted with spherical beads carved out of natural shell resulting in pearls that are characteristically rounder than traditional Freshwater pearls. Akoya pearls have both a higher perceived and actual value than the Chinese Freshwater pearl. Akoya pearls are valued many times more than freshwater pearls of comparable quality. The Akoya oyster is the smallest commercially farmed, pearl-producing oyster. Due to this, the pearls do tend to be small. An average Akoya pearl is only 7mm while an average South Sea pearl is in the 12mm range. Akoya pearls are inherently round, although every harvest produces a percentage of baroque and keshi pearls. These pearls tend to have a bright lustre and shine, common to the Akoya but a shape and look reminiscent of a Freshwater pearl.
Akoya pearls, unless colour-treated, have soft, neutral colours and overtones. Most Akoyas are white to grey with pink, green or silver overtones. Akoya pearls are never naturally black - these pearls have undergone either a radiation treatment or dyeing. While the Akoya pearl is undoubtedly a more rare and valuable pearl than its Freshwater pearl cousin, it is only the third most valuable commercially produced pearl, falling behind White and Golden South Sea and Tahitian South Sea pearls. Akoya pearls, however, can be extremely valuable. Japan was once the undisputed Akoya pearl producing centre of the world but has more recently lost that title to China where, in the last 5 years or so, pearls of equivalent quality have been produced in a much greater abundance. The vast majority of the world's Akoya pearls, of 8mm or larger, are still produced in Japan. However, the Japanese now import many of their smaller Akoya pearls from neighboring China. These pearls are then worked into finished and semi-finished products and sold as Japanese Akoya pearls.