Stones
and Gems," I introduced a chapter on Pearls. But within the last few
years so much information has accumulated, that I felt it impossible to
do justice to the Pearl in any other way than in a separate volume.
Moreover, the fact that a Pearl, although composed mainly of carbonate
of lime, is after all an organic product, renders it desirable to
remove it from association with true minerals. Accordingly in the
fourth edition of " Precious Stones and Gems," I was induced to omit
the description of Pearls, and to promise that the subject should be
separately dealt with in a special work. That promise I have now the
satisfaction of fulfilling.
When
1 first took the matter in hand, I had no idea of the amount of labour
which would be involved in the production of such a work. The study
has, however, been a source of much pleasure to myself, and I trust
that the perusal of the results set forth in this volume, will be
equally a source of gratification to the reader. Although I cannot for
a moment hope that the work is anything like complete in all its
details, yet I may venture to remark that I have spared no pains in
collecting and arranging my materials, and that my information has in
many cases been derived from original sources. At the same time, the
work is not put forth as a scientific treatise, but rather as a
practical guide,
