Saltwater pearls from the Akoya oyster (Pinctada fucata martensii), which are usually cultured. These pearls are typically roundish, and their natural body colors normally range from light pink, to white, to yellowish. The chapters on pearl quality in this book focus on Akoya pearls.

Even though they are often called Japanese pearls, they can also be found in oysters outside Japan. In fact, China has become the major producer of Akoya pearls less than 7 mm in size. Korea, Hong Kong and Sri Lanka are already culturing pearls using the Akoya oyster. Currently, most Akoya pearls over 7 mm are cultured in Japan.