the
same,—hexagonal,—the red variety, or ruby, when not found as a rolled
piece, usually is in the form of a prism, whereas the blue or sapphire
occurs as a double pyramid. The blue is also a little harder and
heavier than the red.
The
ruby was known to the ancients under various names, and was undoubtedly
confused with others widely different. Before mineralogy became a
science, and chemistry could determine the character of minerals by
their composition, stones were named very generally according to their
color. " Car-bunculus," a " fiery red stone," included spinels and
garnets with the harder and more finely colored ruby. \ Only by the
gradual acquisition of knowledge, extending over many years, were the
various stones, as we know them, separated as their different qualities
became known. Some kinds of carbunculus were esteemed more highly than
others, especially one termed lynchnis, because it had a lustre like
that of a lamp. The Greeks wrote of a red stone called anthrax, which
was probably the mineral we know as the ruby. It is doubtful, however,
if any of the ancients recognized the intrinsic superiority of the
ruby. To them the brightest and reddest stone was the best. In
Tavernier's time all colored stones were called rubies in Pegu, and
were distinguished by a prefix of color. There, a sapphire was known as
a " blue ruby." Some think that the " adamas" of early Greek writers
was a corundum and not a diamond. The probability is that the name was
applied to both when they presented a similar appearance. A lustrous
stone, if colorless or nearly so, would be " adamas," whether diamond
or white sapphire, and a fiery red stone was termed carbunculus,
lychnis, or anthrax, though in either case it may have been ruby,
spinel, or garnet.
The
corundums crystallize in the hexagonal system, the ruby generally
taking the form of a hexagonal prism or six-sided crystal: the sapphire
that of a double six-sided pyramid ; but the system of crystallization
is rarely discernible in the rough as it is found. The crystals are
usually rough,
7 '
