Finally found the original question.
Jim, The size of the original seed is negligible. It is very very
small in the case of the freshwaters. It is a small piece of the
mantle of another muscle and wouldn’t be of consequence. In a
saltwater pearl however, the mother of pearl bead inserted into the
akoya oyster can be very significant indeed. The usual time frame
for a saltwater is three years, therefore the nacre coating would be
whatever the oyster can deposit in three years time. Anything less
would result in a pearl of lesser quality, tending to chip or
otherwise not have the luster that would be desirable. These are
sometimes offered at a great discount and are generally NOT a good
buy. (Trivia: The most sought after mother of pearl shell preferred
for saltwater pearl production comes from the Tennessee,
Mississippi!). I suggest that you explore Fred Ward’s book on Pearls
that should run you about $16. It is good and to the point.
When I buy pearls, these are the things I look for: 1) Luster.
Without it, they are just beads. 2) Color. As you pointed out,
overtones of pink are preferred by the caucasian population.
Hispanics find that a gold overtone blends nicely with the Latin
skintone. I try to have a wide assortment available to please almost
everyone. 3) Shape. Although not as important as it once was, round
is still probably the most preferred for necklace strands. I have
had great success with baroque’s both in strands and in designer
rings and pendants. China is doing some really cool things with
pearls these days, which brings me back to youyr original question.
In some of the new extra large Chinese freshwater round pearls, they
are using a new technique (we think, we cannot be sure as they will
not tell us and I cannot blame them) where they take say a 6mm
roundish freshwater pearl, mill it to true round and then insert it
into the freshwater muscle similar to the process used in saltwater
pearl to let it again be coated with nacre and become quite sizable
and still retain the roundness. They are quite striking, though not
of the quality of Tahitians. We have cut them in two and in three
and probably four and this is what we (America) surmises they do. To
fully see the amount of nacre coating on a saltwater pearl
(thickness of coating) one must literally X-ray the pearl. It is
sometimes wise to ask the dealer if they have an idea of the mm of
thickness (if they know). In summary, the more you handle pearls,
hold them, look closely at them and shop around, the more familiar
you will be and the differences should become apparent. Suzanne