the
deep-red coloured stones which were used for Jewelry and Gems, in his
day ; comprising the Ruby, and the Spinel, as well as the various kinds
of Garnet. In the setting of Carbuncles a Ruby-like glow is frequently
communicated to the Stones by a backing of coloured metallic foil which
modifies their hue. This practice was similarly employed in former
Roman times;—"tanta est in illis occasio arte subditis per qua?
transiucere cogantur." The finest Carbuncles come from Ceylon. Milton
gives his Serpent eyes of Carbuncle: " His head crested aloft, and
Carbuncle his eyes." Epiphanius has said about the Carbuncle : When
worn it is impossible to conceal this Gem ; for, notwithstanding with
whatever clothes it may be covered, its lustre shows itself outside its
envelope ; whence it is called " the Carbuncle."
Lychnites : the Lamp Stone—Greek, nultalopos—
another name for the Carbuncle, was said, if hung round the neck, to
give the power of seeing in the dark. It was further reputed to cure
fluxions of the eyes if tied in a linen cloth upon the forehead. Thus
wrote Psellus, De Laipidibus.
Similarly
with regard to the Rock-Crystal (a form of Quartz) as a burning Glass ;
Pliny saith : "I find it asserted by Physicians that when any part of
the body requires to be cauterized it cannot be better done than by
means of a Crystal-ball held up against the Sun's rays." Crystals were
employed thus by Surgeons, in old Roman days, who used the balls as
lenses to burn out sores.
Exposure
to sunlight has a curious effect on some Gems; Garnets, for instance,
lose much of their colour in the course of time if they are worn
continually by day.
