The Akoya pearl is the classic pearl of the single-strand necklace. It grows in the oyster Pinctada fucata, mainly off Japan and in China. Harvested pearls usually measure 6 to 8 mm in diameter, rarely more than 9 mm. Typical are white to cream with a rose or silver overtone and a sharp, almost mirror-like lustre.
They are cultured with a bead: a nucleus made from mollusc shell and a piece of mantle tissue are implanted, after which the oyster stays in the water for 10 to 24 months. Each oyster carries only 1 to 2 pearls. At 0.3 to 0.5 mm the nacre is thin, with good pieces reaching 0.8 mm. The top quality is called Hanadama and is certified by the Pearl Science Laboratory in Tokyo.
Compared with South Sea and Tahitian pearls, the Akoya is smaller and less expensive; compared with the freshwater pearl, it is rounder and more lustrous. The differences in detail are shown in the comparison of the four pearl types.
