Amazonite_" was originally
misnamed, as none is found along the river of that name. The term has
come into such general use, however, that we shall probably have to
continue to use it, especially as no other name has come into use for
this bluish-green feldspar. As has already been said, amazonite is
sometimes sold as "jade," which is incorrect.

MALACHITE, AZURITE, AND LAPIS LAZULI. _Malachite_ and _azurite_ are
usually correctly named, but "_lapis lazuli_" is a name that is
frequently misused, being applied to crackled quartz that has been
stained with Prussian blue, or some other dye, to an unconvincing
resemblance to true lapis. Such artificially produced stones are
sometimes sold as "_Swiss lapis_." They are harder than true lapis and
probably wear much better in exposed ornaments, but they are not lapis
and are never of equal color, and names should not be misused, and
especially is this true in a trade where the public has had to rely so
completely upon the knowledge and the integrity of the dealer.

With the increase of knowledge about precious stones that is slowly but
steadily growing among the public, it becomes more than ever necessary
for the jeweler and gem dealer to know and to use the correct names for
all precious stones. The student who wishes to learn more about the
matter will have to cull his information from many different works on
gems. G. F. Herbert-Smith, in his _Gem-Stones_, gives a three and one
half page chapter on "Nomenclature of Precious Stones" (Chap. XIII., pp.
109-112). The present lesson has attempted to bring together in one
place material from many sources, together with some suggestions from
the author.

LESSON XXI

WHERE PRECIOUS STONES ARE FOUND

OCCURRENCE OF DIAMOND. Every dealer in precious stones should know
something of the sources of the gems that he sells. The manner of the
occurrence of the rough material is also a matter of interest. It will
therefore be the purpose of this lesson to give a brief account of the
geographical sources of the principal gems and of their mode of
occurrence in the earth.

For the sake of uniformity of treatment we will once more follow the
descending order of hardness among the gems and we thus begin by
describing the occurrence of diamond. It will be of interest to note
first that the earliest source of the diamond was India, and that for
many years India was almost the sole source. Tavernier tells us that the
diamond mining in