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Ruby 2
Occurrence The rubies with
the finest color come from the Mogok region in Burma. These
are most truly vermilion, though they still have a touch of
carmine. Thailand, however, is today the main source of rubies.
Thai rubies are usually slightly less attractive, a bit darker
with a violet tinge, but they often have fewer inclusions.
Rubies are also found in Sri Lanka, but in very small quantities.
Often pale, almost pink, they can be attractive,
with an appearance that is both brilliant and lively. Small
quantities of very fine rubies also come from the area of
Cambodia on the border with Thailand, while rather opaque
specimens, mainly of inferior quality, are found in India
and Pakistan. Tanzania and neighboring countries have also
been mining rubies for a few years. Some of the rubies found
in these countries are almost as finely colored as those from
Burma, with inclusions similar to rubies from Thailand, while
others are semiopaque and of very limited value.
Value The highest quality, best colored and
most transjewelry with ruby parent stones (usually from Burma),
weighing, for example, and diamonds. 3 to 5 carats, can be
as valuable as diamonds, or even more so. Very good quality
rubies of even greater weight are extremely rare and fetch
exceptionally high prices. Good quality stones of at least
2 carats (a bit more violet in color and usually from Thailand)
are still quite valuable (particularly the more transparent
ones). The price falls considerably for stones of less than
a carat, which are too dark in color, and have inclusions
clearly visible to the naked eye.
Simulants and synthetics Ruby
has very occasionally been imitated by glass, which has a
rather different, less lively color and an inferior luster.
It has sometimes been imitated by doublets, with the top part
consisting of garnet, to provide luster, hardness, and natural-looking
inclusions and the bottom part of red glass, fused rather
than cemented to the garnet layer. But such imitations are
uncommon. Synthetic ruby has been produced from the beginning
of the twentieth century and was the first synthetic gemstone
to be manufactured on an industrial scale.
To make these synthetic stones harder to distinguish
from some natural rubies with numerous inclusions, they have
sometimes been fractured internally by heating and rapid cooling.
More recently, doublets imitating rubies have also been produced
in the Orient. The top part of these doublets consists of
poorly colored (usually pale green or yellow) natural corundum
with obvious, typical inclusions; and the lower part is synthetic
ruby, held to the corundum by transparent cement. The effect
is highly deceptive: the reassuring presence of natural inclusions
and characteristic luster combined with a color which is not
perfect, but is normal for the majority of rubies, can be
much more convincing than a synthetic ruby.
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