Akoya pearls

Akoya pearls are the pearls behind the classic white strand. They grow in the saltwater akoya oyster, Pinctada fucata, farmed in Japan, Vietnam and China. Japan is historically recognized as the birthplace of modern pearl culturing, and Kokichi Mikimoto cultured a pearl there in 1893 (GIA).

What akoya pearls look like

• Size: usually 6 to 9 mm. Akoyas over 9 mm are considered larger and rarer (GIA).
• Color: white is the classic bodycolor, often with a rose overtone. Blue akoyas also exist and are rare, with a silvery gray tone.
• Shape: round and near-round shapes are emphasized for traditional strands.
• Luster: a sharp, mirror-like shine is what akoyas are known for.

How they are grown

Each akoya is bead-nucleated: a shell bead is placed inside the oyster, and the oyster coats it with nacre. An oyster usually grows one pearl at a time, and culturing takes 10 to 24 months (GIA).

Hanadama

Hanadama means "flower pearl." It is a Japanese trade term for top-quality akoya pearls, and hanadama grading requires round to near-round shapes (GIA). If a strand is sold as hanadama, ask who issued the report.

Watch for

• Dyed pink. Akoyas with a very even pink color may be dyed. Look in the drill hole and in any cracks or pits for concentrated pink dye (Jewelry Business).
• Dark akoyas. A black or dark gray cultured pearl under 8 mm is likely a dyed akoya or freshwater pearl, because natural-color dark pearls (Tahitian) are usually larger (Jewelry Business). Irradiation can also turn pearls dark gray (GIA).
• Thin nacre. Because akoyas have a bead inside, the nacre around it matters. GIA checks nacre so cultured pearls are durable.

Akoya or freshwater?

The two can look alike. Akoyas are saltwater, rounder, sharper in luster and usually cost more. Freshwater pearls are almost solid nacre and come in more colors. Full comparison: akoya vs freshwater.