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carefully guarded secrets, became known as the House of Mystery.
There, under conditions designed to duplicate a natural environment,
Bostwick's mussels, with nuclei implanted according to this American's
theories, began their development. Four years later he obtained his
pearls, many weighing up to ten grains. (2)

Bostwick spent six more years in this House of Mystery
laboratory seeking a means to control size and color in his products.
Then, still in quest of knowledge, he came to Florida and began his
experiments with conchs. After he produced a 43 1/2-grain pink gem,
Bostwick moved to California where he continued his researches in the
Scripps Institute of Oceanography at La Jolla. (2)

The cultured pearls, by reason of their appearance, usually can be
distinguished from natural pearl by an expert. The finer grades of
cultured pearls, however, offer no such means of distinction and it is
only by examining a cross section that they can be separated from the
natural pearls. To so expose the interior means the destruction of a
valuable jewel. To avoid this French scientists developed the endoscope
an instrument which casts a powerful light into the holes of drilled pearls.
In this way, jewelers can no determine if a pearl is natural or cultured
and, if it is cultured, they can measure the size of the nucleus and the
thickness of its pearly covering. With this instrument an experienced
man can examine 150 pearls per hour. (1)

The difference between a natural and a cultured pearl lies chiefly
in the outer skin covering. In cultured pearls this averages