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Ruby : King of Precious
Stones
Ruby has been the world's most valued
gemstone for thousands of years. Ruby was said to be the most precious of the
twelve stones God created when he created all things and this "lord of gems" was
placed on Aaron's neck by God's command. The bible says that wisdom is "more
precious than rubies," that is to say very valuable indeed. In the ancient
language of Sanskrit, ruby is called ratnaraj, or "king of precious stones" and
ratnanayaka, "leader of precious stones."
In fact, rubies are today still more
valuable and rare than even the top quality colorless diamonds. A 16 carat ruby
sold at auction for US$227,301 per carat at Sotheby's in 1988. A 27.37 carat
Burmese ruby ring sold for US$4 million at Sotheby's in Geneva in May 1995, or
$146,145 per carat. A 32 carat ruby sold for US$144,000 per carat at Sotheby's
in 1989. In contrast, eight D-color internally flawless diamonds over 50 carats
were sold in the past 9 years and the largest, a pear-shape of 102 carats,
fetched a mere US$125,000 per carat. Top rubies are so rare even the world's top
gem dealers must incessantly comb estate sales and auctions to find them. Sizes
above five carats are particularly rare.
Ruby is the gem quality of the mineral
corundum, one of the most durable minerals which exists, a crystalline form of
aluminium oxide. Corundum has a hardness of 9 on the Mohs scale and is also
extremely tough. In its common form, it is even used as an abrasive.
Choosing a Ruby
The most important factor in the value
of a ruby is color. The top qualities are as red as you can imagine: a saturated
pure spectral hue without any overtones of brown or blue. The word red is
derived from the latin for ruby, ruber, which is derived from similar words in
Persian, Hebrew, and Sanskrit. The intensity of color of a fine ruby is like a
glowing coal, probably the most intensely colored substance our ancestors ever
saw. It is no wonder they ascribed magical powers to these fires that burned
perpetually and never extinguished themselves.
All colors of corundum except red are
known as sapphires, which has created controversy about where ruby ends and
sapphire begins, particularly in pink shades of corundum. In 1991, the
International Colored Gemstone Association ruled that the lighter shades of the
reddish hues of corundum should be included in the category of ruby.
After color, the other factors which
influence the value of a ruby are clarity, cut, and size. Rubies that are
perfectly transparent, with no tiny flaws, are more valuable than those with
inclusions which are visible to the eye. Cut can make a big difference in how
attractive and lively a ruby appears to the eye. A well-cut stone should reflect
back light evenly across the surface without a dark or washed-out area in the
center that can result from a stone that is too deep or shallow. The shape
should also be symmetrical and there should not be any nicks or scratches in the
polish. Rubies and other gemstones are sold per carat, a unit of weight equal to
one-fifth of a gram. Larger rubies, because they are more rare, will cost more
per carat than smaller stones of the same quality.
Ruby sometimes displays a three-ray,
six-point star. These star rubies are cut in a smooth domed cabochon cut to
display the effect. The star is best visible when illuminated with a single
light source: it moves across the stone as the light moves. This effect, called
asterism, is caused by light reflecting off tiny rutile needles, called "silk,"
which are oriented along the crystal faces.
The value of star rubies and sapphires
are influenced by two things: the intensity and attractiveness of the body color
and the strength and sharpness of the star. All six legs should be straight and
equally prominent. Star rubies rarely have the combination of a fine translucent
or transparent color and a sharp prominent star. These gems are valuable and
expensive.
Where Rubies are
Born
The most famous source of fine rubies
is Burma, which is now called Myanmar. The ruby mines of Myanmar are older than
history: stone age and bronze age mining tools have been found in the mining
area of Mogok. Rubies from the legendary mines in Mogok often have a pure red
color, which is often described as "pigeon's-blood" although that term is more
fanciful than an actual practical standard in the trade today. Myanmar also
produces intense pinkish red rubies which are also vivid and extremely
beautiful. Many of the rubies from Burma have a strong fluorescence when exposed
to ultraviolet rays like those in sunlight, which layers on extra color. Burma
rubies have a reputation of holding their vivid color under all lighting
conditions.
Since demand for fine rubies is really
only limited by the tiny supply available, new sources are always treated as
exciting news in the trade. An important mining area in Burma is called Mong
Hsu.
The Mong Hsu ruby deposit is producing
commercial quantities of commercial quality Burma ruby and also significant
quantities of fine quality Burma ruby, particularly in sizes up to a carat.
Burma ruby is now more readily available than Thai ruby, due to the new ruby
rush in the area.
The new deposit has also affected the
world capital of the ruby business: Thailand. Many of the ruby traders and
cutters from Chanthaburi and Bo Rai have moved to Mae Sai in Thailand. In
Tachilek in Myanmar, across the border from Mae Sai, a flourishing trade in Mong
Hsu ruby has transformed a village into a prosperous town. Most Mong Hsu ruby is
cut and marketed in Thailand.
Thailand is the world's most important
ruby trading center. Perhaps 80 percent of the world's ruby goes through
Thailand at some point in the trading cycle. The largest ruby cutting factories
are in the Chanthaburi area of Thailand. Bangkok is generally where the world's
buyers come to purchase ruby.
In 1992, a new ruby mine was discovered
in Vietnam that produces rubies which are very similar to rubies from Burma. In
fact, the geology of the new mine may be a continuation of the same formation
that produced the Burma deposits. Some of the new Vietnamese rubies have been
praised by experts as being virtually indistinguishable from top quality Burmese
stones.
Fine rubies are also found in Thailand.
Thai rubies tend to be darker red in tone: a real red, tending toward burgundy
rather than pink, as Burma rubies do. This makes them very popular in the United
States where consumers generally prefer their rubies to be a darker red rather
than a darker pink. Some Thai rubies have black reflections, a phenomenon called
extinction, which can make their color look darker than it really is. But Thai
rubies also can have a rich vivid red that rivals the Burmese in intensity. Sri
Lankan rubies can also be very beautiful. Sri Lankan stones are often pinkish in
hue and many are pastel in tone. Some, however, resemble the vivid pinkish red
hues from Burma.
Rubies from Kenya and Tanzania
surprised the world when they were discovered in the sixties because their color
rivals the world's best. Unfortunately, most of the ruby production from these
countries has many inclusions, tiny flaws which diminish transparency. Rubies
from the African mines are rarely transparent enough to facet. However, their
fantastic color is displayed to full advantage when cut cabochon style. A few
rare clean stones have been seen which are top quality.
Occasionally a few fine top-quality
rubies appear on the market from Afghanistan, Pakistan, or the Pamir Mountains
of the Commonwealth of Independent States. The terrain in these areas has made
exploration for gemstones very difficult but someday they may produce
significant quantities for the world market.
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