[xeresana]

Can someone help me understand the history of nacre thickness? I was reading some back posts that indicated that older akoya had thicker nacre. How thick and when did it change? For example, how thick would the nacre have been on a strand from the '50s vs the '70s vs the '90s?

Thanks.

[jerin]

When Mikimoto started cultivating the Akoyas the nucleus with the mantle tissue used to stay longer than now. Probably the nacre was at it´s thickest in the 50´s. 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.

[xeresana]

Thanks! Do we know how thick the average nacre was in the '50s?

[Pearl_dreams]

In the August 1985 National Geographic article "The Pearl" by Fred Ward, there is this quotation from a Mr. Hamaguchi of the Yamakatsu Pearl company (pages 205-206):

"Before 1960 we kept the oysters in the water for two and a half years. Then we dropped the time to one and a half years and held there until 1979. Now the culture takes six to eight months. It's all a matter of time and money."

[Valeria101]

Nacre thickness wasn't a sale point until it became a problem, was it?

Never found any report describing the nacre thickness of older Akoya, just the cultivation times as already cited here, and assumed it is a reasonable guess to say that thrice the time means thrice the nacre thickness (or at least more then twice).

Just a thought.