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The exact date when rubies were first
discovered at Mogok is unknown. No doubt the first humans to settle the area
found rubies and spinels in the rivers and streams rubies occur in a
crystalline limestone (marble). Bit by bit, millions of years of weathering
freed the rubies from their marble womb, carrying them down from the hills
to the valley floors, where they have settled in the bottom of the streams
and rivers. It is from these ancient river gravels (locally termed byon)
that the majority of stones have been recovered.
Rubies vary widely in color, ranging from rose red through so-called ruby
red and carmine to a deep purplish red, called pigeon blood -- the most
highly prized color variation. When cut into a cabochon (a convex, unfaceted
form), some specimens of ruby exhibit asterism; that is, a six-rayed star
can be seen in the interior of the stone. Such stones are called star
rubies. When exposed to high temperatures, rubies turn green, but they
regain their original color after cooling.
Many gemstones that are not rubies are also
called rubies. The balas, or balas ruby, for example, is a type of spinal.
The Bohemian ruby is derived from rose quartz, while the Siberian ruby is
red or pink tourmaline. The American ruby, Cape ruby, Montana ruby, and
Rocky Mountain ruby are varieties of garnet.
Synthetic rubies were first produced in
1837. Improvements in the manufacturing methods of synthetic rubies, which
are very much like the natural stone in physical and chemical properties,
have made the synthetic gems cost effective to produce. Although synthetic
rubies are used as gemstones, at least 75 percent of the annual production
of synthetic rubies are used in the manufacture of watches and instruments.
Ruby has been the world's most valued
gemstone for thousands of years. In the ancient Sanskrit language, it
was called ratnaraj or "king of precious stones". Even today, rubies are
considered more valuable and rare than even the top quality colorless
diamonds.
Rubies occur in a
number of countries. Burma (Myanmar) is most famous as a source for
both. Burmese rubies and sapphires fetch a premium in the market because
of their perceived superior colors. Burma ruby prices soared during the
1980s and only abated with a new discovery at Mong Hsu. Rubies are also
found in Thailand, Cambodia, Kenya, Tanzania, Afghanistan, India, and in
a small non-commercial deposit in North Carolina. Sapphires are mined
commercially in Thailand, Australia, China, Tanzania, Mozambique, Kenya,
Nigeria, and, surprisingly, in Montana. In fact, as pointed out in our
new book, Montana is one of the gem trade's best-kept secrets. Large
quantities of very colorful sapphires are quietly produced in the U.S.
For maximum color impact, nothing surpasses rubies. Often expensive,
their price is justified because rubies are at least 50 times rarer than
equivalent diamonds yet priced at only a small premium.
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Perfect
natural gems in color and appearance are very rare and expensive. Controlled
heating is commonly used in the trade to produce, intensify or lighten color
and/or improve clarity. This allows the trade to bring more, better quality gems
to the market. Heat enhancement is permanent and stable.
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