tions, of which pearls are the result. There seems to exist no inherent cause why Anadon cygnea, with its beautiful silvery nacre—as bright often, and always more delicate, than that of Unio margaritiferus—
should not be equally productive of pearls; but secure from violence in
its still pools and lakes, and unexposed to the circumstances that
provoke abnormal secretions, it does not produce a single pearl for
every hundred that are ripened into value and beauty by the exposed,
current-tossed Unionidae of our rapid mountain rivers. Would that
hardship and suffering bore always in a creature of a greatly higher
family similar results, and that the hard buffets dealt him by fortune
in the rough stream of life could be transmitted, by some blessed
internal pre-disposition of his nature, into pearls of great price."1
The small blue mussel (Mytilus edulis) of
the British seas yields opaque pearls of a deep blue color, but most of
them are more or less white in some part. Sometimes a shell is found in
which a blue pearl will be adhering to the blue lip of the shell while
a dull white one adheres to the white portion of the shell. These
pearls are commonly flattened on one side, doubtless where they have
been adjacent to the shell. None of them is of more than very slight
value.
Probably
the principal fishery for the salt-water mussel pearls is that in the
estuary of the Conway in Wales. These are mostly quite small and well
answer the designation of seed-pearls, although a few are of fair size.
In color most of them range from dirty white to the dusky or brownish
tint noted by Tacitus eighteen centuries ago, but a few are of a pure
silvery tint. In some seasons London dealers have agents at Conway for
purchasing these pearls. The price is usually from eight to thirty
shillings per ounce.
