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only about three or four hundredths of a millimeter in thickness. By
implanting a good-sized mother-of-pearl nucleus as a beginning it is easy
to see how a pearl of more than average size could be obtained much
more quickly than one could be obtained by starting with a grain of sand
or other object which might become imbedded in the tissue. The genuineness
lies in the amount of natural pearl formation. Natural pearls have been
found having no central nucleus. Scientists learned that they, too, could
induce mollusks to produce such pearls by transplanting epithelial cells
from one oyster or mussels to another but the gems so produced were badly
formed. (1)

The peculiar iridescence of the pearl produced by the interference of
light rays reflected by exposed edges of the nacre can be imitated by
artificial striation or microscopic corrugations on many materials. In 1860,
Jacquin, a rosary maker in Paris, learned how to make excellent imitations of
pearls, and since then many methods have been discovered. (1)

Jacquin made small spheres of thin glass and reproduced the
iridescent effect by lining the inside walls of these spheres with the
shining scales of a small fish known as the bleak. The cavity was then
filled with white wax. Fine-grained hematite, not highly polished,
greatly resembles black pearls while pink ones have been imitated by
turning small spheres from tinted sections of conch shells or from pink
coral. (1).