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Gemstone Infocenter
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Comprehensive Gemstone
Information
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Emerald - Birthstone
of May
Part 2
When talking of pricing real estate, there is a popular saying that the top 3
factors that influence price of real estate is location, location, and location.
This may also be true in case of emeralds. When we think of quality emeralds, we think of Columbia and Muzo mines. In
fact some people just call a vivid, slightly bluish green stones of medium to
medium dark color as Columbian Emerald although it may not have come from
Columbia! Colombia is by tradition and lore, the finest modern source for
Emeralds.
Colombia and Brazil are the two major producers of emerald. While Colombian
Emeralds are known for their vivid green color, Brazilian Emeralds are known for
their variety of colors. They can range from light green to fine to medium dark blue
green.
Historically the emeralds given to Cleopatra came from Africa. But
these mines have long been closed. At present, there are emerald mines in
Zambia, Zimbabwe, Madagascar and Nigeria. Each of these location typically
produces a certain color, size and clarity. For example, Zambian Emeralds are of high quality
but not as neon green as Colombian Emeralds. They occasionally show a very slight
brown or yellowness in color. Although Zambia has the world's second largest
Emerald deposit, this is substantially underdeveloped and restricted to
approximately 40 mines in
Northern Zambia.
The USA and Japan together purchase more than 75% of the world's cut
emeralds.
Emerald, by definition, is a medium or darker green to bluish green beryl, in
which the green color is derived from impurities of chromium or vanadium or a
combination of both.
Presence of iron will affect the color of emerald. It gives the emerald a
bluish tone.
GIA classifies emerald as a "Type III" gemstone. This is because emeralds are
virtually always included to one degree or another. This means that the clarity
grades for emerald is different than what we use for other colored stones. For
example, a clarity grade of "very slightly included", refers to the normal range
for emeralds.
Well over 90% of the emeralds in commerce have been treated to minimize the
appearance of the inclusions. The industry practice for treatment is called "oiling".
This refers to the practice of immersing emeralds in a
colorless oil or resin of natural or man-made origin. Often this is done using a
vacuum chamber to assist in penetration.
Non-standard treatments go beyond this to using green colored oils and
hardened (epoxy-like) resins. These treatments dramatically improve the
appearance of the gems, but necessitate special care in cleaning and setting.
Steam cleaners, solvents and ultrasonic cleaners can remove the oil, making inclusions,
which had barely been visible before cleaning, stand out in sharp relief.
It is possible to have emeralds re-oiled.
Next: Jewelry Design Considerations
[ Emerald part 1 ] [
Emerald part 3 ] [
Emerald part 4 ]

See Also:
Products with Emerald
Therapeutic Power of Emerald
Gemstone Infocenter Home
Gift Selections incorporating Gemstones
Guide to Caring for Gemstones
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