Large baroque pearls from Tahiti, the South Seas, and China labeled as keshi have been coming into the U.S. market, so we asked pearl expert Giuseppe Lombardo of the Pearl Exporting Co., Kobe, Japan, to answer a few questions about keshi pearls.

JCK: What is keshi?

Giuseppe Lombardo:Keshi is actually a term derived from the Japanese word for “poppy seed,” and is traditionally used to describe small, seed-size pearls found as unintentional byproducts of culturing bead-nucleated Japanese akoya cultured pearls. Keshi, like natural pearls, are formed when an irritant makes its way inside the oyster, and nacre (mother-of-pearl) is laid down to protect the oyster from the foreign object. In the marketplace, many dealers are using the term keshi and referring to Chinese freshwater pearls. Chinese freshwater pearls are not the traditional keshi.

JCK: Are they easy to find?

GL: Currently, the supply of Japanese akoya keshi pearls is diminishing, due to many different reasons, among them pollution and the way that the cultured pearls are harvested. In the past, the pearls were removed by hand, but now the pearls are taken out by machine, which causes the small keshi to be washed out. As a result, the total Japanese akoya production containing keshi is now less than one-half of 1 percent.

JCK: What are typical sizes and qualities?

GL: Akoya keshi sizes range from 0.6 mm (which are drilled by hand) up to 4 mm. They sometimes, on a rare occasion, can get as large as 7 mm, but generally speaking the larger they get, the lower the quality and less usable for jewelry purposes. Colors range from white to cream and gold, and a variety of overtones of silver and gray. With regard to quality, it’s more shape-based. Since these pearls are formed without a nucleus, shapes tend to come more baroque, with round being very rare. Other shapes include rice, oval, flat, and semi-round. The round keshi pearls are so rare that they are sold by the carat. Normally you may see 0.01 percent perfectly round, so to make strands are quite rare indeed. A few strands of round akoya keshi pearls may take 10 years to collect.

One of the remarkable things about Japanese akoya keshi pearls is that their color and luster remain unchanged through time and are 100 percent nacre.