outside.
Undoubtedly pearls containing hidden qualities which made them once
gems are thrown away as valueless, while others found just as nature
had covered their earlier coarseness with a coat of beauty, are worn
and excite much admiration for their skin-deep beauty.
Though
the successive skins of a pearl do not usually vary much in color,
except in abalone pearls, it does happen occasionally, for the removal
of dark yellow skins sometimes discloses another of better color — a
good pink for instance. From the sectional appearance of pearls it
seems probable, that in the majority of cases the color of yellow
pearls would be improved by the removal of the outer waves of the outer
skin.
Changes
in shape sometimes occur during the growth of the pearl, the tendency
being always toward the rounding of the surface. If the nucleus is fast
to the shell, a dome is built over and around it. If the nucleus
permits, the nacre is deposited not only over but under its edges to
the point of contact with the shell, so that a button pearl connected
with
158
