giving
depth and the diamond adding its lustre, the composite stone being sold
as a diamond. Then there are the zircons, these stones are composed of
30 per Gent of silica and 67 per cent of zirconia, and their value is
comparatively-trifling. Their lustre is adamantine, but their colours
would betray them at once, even to the most careless observer. A means
is known, which, moreover, is qxtensively employed, by which the
colours are extracted from these stones, leaving them to all appearance
diamonds, till submitted to tests, when, of course, they are at once
detected." *
"
Are rubies ever manipulated ?" " Not so far as I know—that is to say,
not in the way you mean, but a red spinel is more often sold as a ruby
than the-real stone—that is the corrundum ruby—which latter is harder
and much wore valuable. In the same way French compositions—in which
the usual flaws found in nearly all emeralds are carefully imitated—are
substituted for and sold as emeralds. It would take an expert to detect
these when mounted in an article of jewellery."
" Dy«d! what, are precious stones then dyed, in these days of shoddy, ehina clay, veneer, and Imperial Institutes?"
"Certainly.
They are dyed, and in many cases dyed right through, so that you might
break your specimen and discover the various colours, say in agates,
passing right through the specimen—much to your unsophisticated
satisfaction. There is an industrial village called Oberstein, on the
Nahe, and not far from the Rhine, which I have visited, and concerning
which I can therefore speak from personal experience. That village is
occasionally visited by English people, who, after inspecting its
shops, fancy—as tourists delight to do—that they have discovered an
unknown source of precious things. Exquisite jewellery, superb lapis
lazuli necklaces, every bead of which is a treasure, gorgeous agates,
marvellous crocidolite of undreamed-of tints, of late even a blood-red
tint has been obtained! Alas! for the tourist's future self-confidence,
when on his return home he finds his jewellery all brass, his lapides
all dyed. That village's industry is devoted to the making of what is
known as Brummagem jewellery, and the dyeing of chalcedony &c, for
export. Its products are sold everywhere."
"
Pleasant, very ! Can you explain the process, as it seems extraordinary
that anything so hard as agate should be capable of being dyed right
through ?"
"
Agate is only one form of chalcedony oat of many. The onyx, carnelian,
bloodstone, are other forms familiar to most people. I saw the
processes, but the workers were too wary to explain their secrets.
Different families have different processes for producing similar
results, and in some cases one family's process will fail with a given
piece of stone when another's will succeed. It is impossible for the
most experienced experts to say beforehand without a trial what colours
the various bands of the chalcedony will take. Before purchasing 'lots'
of stone for manipulation at the auctions whence the supply of raw
material is obtained, every bit or piece of each ' lot' has to be
tested by trial, small chips being used for this purpose. As regards
the processes, all,I can say is that in the cise of agates and onyxes,
these being ' banded chalcedon'—that is, chalcedony with bands of
various degrees of density—-the specimens are placed in pots containing
the colouring matter and are then subjected to great heat for periods
varying from a few hours up to a fortnight or more. Certain bands take
the colour, others do not. The stone is, after the first, given a
second, and perhaps several more, stewings in pots containing different
colouring mixtures. In time every band has received the colour partial
to it, so to speak. The results are the beautiful onyxes and agates you
see everywhere. The carnelian not being banded, and being of a
different density, is treated differently, to enrich the natural
colour, heat being the most potent factor. Fluorspar is capable of
great improvement in its appearance by being
* Matura diamonds" are zircons, from which colour has been expelled b7 fire heat.—Compilers.
