smaller gems, such as small roses, rubies, emeralds, garnets, turquoise, &c.
The jewellers' wax used for mounting gems is made of three parts rosin, one part beeswax, and four parts fine brickdust.
CLEANING THE GEMS.
The
following composition I have found to be the best for thoroughly
cleaning gems, particularly when set: Take one part flowers of sulphur
and two parts of rotten-stone or bone-ashes, which, when mixed, is used
by rubbing it on a piece of buckskin, and with that and a stiff
hair-brush, alÂternately rubbing the gems, finishing with a softer skin
or cloth to remove the dust.
IMITATIONS OF GEMS.
Pliny
mentions the imitation of jewels by glass fluxes, and it is
sufficiently proved that the ancients were far adÂvanced in this art.
The Egyptian mummies were provided with glass buttons of green and blue
color, and during the reign of the Roman empire, colored glass was very
general; and we find antique cameos carved in various colored glass,
representing the onyx; likewise colored glass cemented with real onyx;
but they never attained such perfection in their art as to set at
defiance the skill of the artist and jeweller to distinguish between
the genuine and spurious ones. The imitation of gems may be divided
into three classes:
A. The Pastes. The basis of these imitations is a fine, pure, and white glass composition, called strass, after
its inventor, Strass of Strasburgh, in the seventeenth century, who
first conceived the importance of imitating the real gems as respects
their hardness, specific gravity, and re-
