The word ”Keshi” is Japanese for ”seed pearl” and indicates a very small pearl. Today Keshi pearls can be found in larger sizes, as also the big South Sea and Tahiti pearl oysters produce Keshi.
Keshi is pure mother-of-pearl and considering its growth pattern, very close to a natural pearl. A Keshi pearl comes into existence in the South Sea and Tahiti oysters by a coincidence when the pearl oyster has managed to belch out the inserted nucleus, but the process of creating the mother-of- pearl continues. The South Sea and Tahiti oyster will always present either a pearl or a Keshi. As a difference to this, the Akoya Keshi can be found in the mantle tissue of the oyster and can be additional to the cultured pearl.
The name Keshi should only be used for pearls coming from saltwater pearl oysters.
Akoya Keshi are formed after the grafting of the oyster. During the grafting process, small pieces of tissue can be disengaged and wander to the outer mantle tissue of the oyster where they are then formed to Keshi. When the pearl harvest is taking place every oyster will be examined in order to see whether it should carry one or more Keshi pearls. These Keshi are present together with the pearl as the place of growth is different from the one of the pearl. The average size of Akoya Keshi is 1-3mm, though up to 5mm can be found in very baroque shapes. The quality of Keshi is very varying.
It takes a great deal of skill and patience to sort, grade and drill these tiny pearls. Shapes, qualities and colours are to be evaluated where after the drilling, which is always done by hand, can take place.
Akoya Keshi are found in natural colours of white, crème and silver.
New harvesting methods are beginning to be implemented for the Akoya cultured pearl. This means that the mantle tissue of the oysters will be left unexamined and only the actual pearl will be harvested. Consequently, the Akoya Keshi will become more and more rare. Today, Akoya Keshi represents less than 0.5% of the yearly Akoya cultured pearl harvest.