October 15th 2008
The Keshi is an other product of pearl farming. They are pearls with irregular shapes and without nucleus. They are similar to natural pearls, made exclusively of mother-of-pearl. The difference is visible only by an X-rays examination.
There are two types of keshis, the first graft keshis and the regraft keshis.
The first garft keshis:
These are the most similar to the natural pearls. They are generally small and rounded, very rarely perfectly spherical, and always with various hues.
To understand the process of making a keshi, we must first understand the graft (cf article). To summarize, the graft is the operation of introducing a piece of mantle of a donor oyster, called the graft tissue, and a nucleus into the gonad of the receiving oyster.
We harvest first graft keshis when the graft operation did not success, because the nucleus was rejected. If the graft tissue hasn't been rejected, which happens frequently, then we can harvest keshis. The graft tissue will develop inside the gonad and will secrete mother-of-pearl on itself, instead of covering the nucleus. In general, we harvest this type of keshis after 18 months of breeding.
We sell keshis as fancy jewelry, sometimes in combination with pearls, or we also sell them by unit or by weight in small lots.
The regraft keshis:
The regraft keshis are with irregular shapes and generally larger than the first graft keshis. We get those from oysters that have already produced a pearl, when the grafter could not graft them again (either because the pearl was not beautiful enough or because the pearl bag tore at harvest).
If instead of eliminating them from breeding, these oysters are put back on the breeding stations, the bag which contained the pearl continues to secrete mother-of-pearl and make a keshis.