old
Hebrew tradition that if a serpent fixes its eyes on an Emerald, it
becomes blind. In the New Testament the Rainbow is said to be " like
unto an Emerald " —(Revelation iv. 3): " And there was a rainbow round
about the Throne, in sight like unto an Emerald."
An
allied variety of Corundum is the Chrysoberyl, or Cat's-eye. This very
brilliant Gem is of a yellowish colour; sometimes brownish yellow, and
occasionally white ; it possesses double refraction to a high degree,
and acquires positive electricity by friction, retaining it for several
subsequent hours. It contains Alumina, Glucina, with the Oxides, of
both Lead, and Copper. Another Chalcedonic variety of Quartz has also
been named " Cat's-eye " ; but this is not the true stone. The true "
Cat's-eye " (which is a rare variety of the Chrysoberyl) exhibits a
remarkable play of light by reason of a peculiarity in its
crystallisation. This ray of light is called " Line " by jewellers, and
is most highly valued when reflected in the popular colours of clear
apple-green, and dark olive. The Cat's-eye is the last jewel a Cingalee
will part with. He believes it to be endowed with every virtue ; and
that its wearer is assured of good luck in all his doings. " The
Stone," says an Indian traveller, " is indeed wonderfully beautiful,
with its soft deep colour, and mysterious gleaming streak, ever
shifting, like a restless spirit, from side to side as the stone is
moved. No wonder that an imaginative people regard it with awe, and
wonder, fully believing it to be the abode of Genii; wherefore they
dedicate it to their gods."
The
Emerald differs from Beryl in possessing a fine green colour ; this
being chemically attributed to the presence therein of chromium
sesqui-oxide; furthermore it never presents the internal stria? which
are so
