| When Mikimoto started cultivating the Akoyas the nucleus with the mantle tissue used to stay longer than now. Probably the nacre was at itīs thickest in the 50īs. From then on it got thinner all the time as the pearls were not allowed to stay in the oyster and now the best are in the oyster for about 18 month, many are only 6 to 12 months in the oyster and that plus several other factors during the growth of the pearl will result in much thinner nacre - thus a certain wearing down of the nacre if the necklace is in daily use. Now the best pearls often have no more than .50 mm (a total of 1 mm) nacre thickness. The Vietnamese Akoyas probably have thicker nacre but once the farmers realize they can make more money by taking them out of the oysters after a fairly short time, the nacre thickness is going to suffer there as well. Production in Vietnam is not large yet.
__________________ Inge Jernberg  |