Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1884-04-05
PRECIOUS STONES.
Interesting Facts Concerning Their
Cutting and Setting.

Interesting Facts Concerning Their
Cutting and Setting.
An expert gives, in a foreign paper, the
following interesting facts with regard to
the cutting and setting Of precious stones
Crystalline gems, like diamond and to-
paz, are generally cut in such manner as
to have flat, smooth faces. Precious stones
that decompose the light, and thus produce
a play of colors, are polished in such man
ner as to highten this effect az much as
possible, which Is accomplished by making
large number of small facets. The brill
liant is an example. Precious stones hat
do not crystalline, and are distinguished by
play of colors, Ike the opal, or pecuE. ef-
fects of light, like the. cats eye, are u ly
polished round or oval, like loaf Of +
or a half Of an egg. Gems are set in ..
different ways, distinguished IS free s.
ting lajolT) and band setting len casette)
In the former the stone is exposed on all
sides and only held by little clasps. All
its properties, its fire, its play Of coloB,
show to the best advantage here. Hence
very valuable gems are never set III any
other way. Flat stones that are set IN
rings are sometimes fastened on the edge,
so as to leave only the top and bottom sur
faces exposed. In the band setting the
stone forms the lid of gold box, and if the
gem is transparent the upper surface Is
generally made fat and smooth, while the
under side forms low pyramid. In those
stones which receive band or box setting
and are less valuable, the beauty Of the
stone is increased by lining the box with
colored tinfoil, the color of the foil core
spending 10 that Of the stone. Thus, for
example, piece Of dark yellow foil Is
placed under very pale topaz, a deep pur-
pie foil under pale amethyst, and 50 on,
- that the light reflected from beneath
through the stone will have deep yellow
or violet color giving the stone much
finer appearance than if II were set free
When setting common stones in cheap
goods, they do not take the trouble to line
the box with tinioil, but merely give it a
coat Of some colored varnish This method
Il not one to be recommended, for a stone
that has the foil beneath II looks much
haudsomer In order to make a cheap
article with genuine stones the following
ingenious device is re-orted to: Thin slips
Of some gem. As emerald, for example, are
backed 10 with a glass Of exactly the same
color, and the glass likewise polished. BY
setting one Of these double stones with the
real stone outward and the glass beneath
the surface viii, of course, exhibit all the
properties Of the gem, such as hardness,
etc These halfgenuine stones are known
as 'underlaid gems, or in French as
pir7res ines doubtless When these under
laid gems are slillfnily set, it Is difficult
even for the expert to distinguish them
from perfectly genuine stone, but still it is
easy to distinguish them by holding the
stone before the eye in such a manner that
the light reflected from the top enters the
eye at an oblique angle; the surface where
the stone and glass meet can be distinctly
recognized by the difference in the re
fractiye power Of the two media, having
the appearance Of a crack or flaw in the
stone The public are frequently deceived
by dealers who represent these underlaid
stones as being perfectly genuine