|
106
|
GEMS.
|
||
|
|
|||
|
Almost
all the Gnostic gems are engraved green jasper. Many carnei of the
Byzantine period are in jasper. About the year 1600, when art began to
decline, sanguineous jasper was used to carve the figure of Christ
crowned with thorns and spotted with the blood which dropped from his
wounds.
Great use is now made of this stone for engravings, carnei, rings, bracelets, strings of beads, and other similar works.
Of the Sicilian jaspers, which are very common with us, cups, knife-handles, tables, altars, even pillars and columns are made.
XXXV.
DICHROITE.
There are
many gems known under different names. The cause of this multiplicity
of names is, in my opinion, that the first persons who found or
observed a gem had not the complete knowledge of the substance of
which it was composed-.
It
is very desirable that custom should prescribe, amongst many, one
single name by which to designate the same stone, always, in order to
prevent confusion in the mind of the student.
Thus
the dichroite is called also, water sapphire, cor-dierite, iolite,
peliom, steinheilite, and prismatic quartz. Amongst all these, we keep
to the first, which is derived from the Greek, and has been given on
account of one of its properties, which is, that of presenting two dif-
|
|||
|
|
|||