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Emerald under a microscope!
image location - microscopy.fsu.edu |
Postage stamps dedicated to Emerald!
image location - stampmin.home.att.net |
The beauty of a fine emerald is unequaled in the world of gems.
Rarely is the stone found without heavy inclusions, but when it is it
is the most expensive and desired gem of all even more so than fine
diamonds. A member of the beryl family, which includes aquamarine and
others, the emerald is a vivid green colored by small amounts of
chromium with traces of iron, or by vanadium. All stones contain
inclusions, and only a very few even approach a level of clarity that
would be acceptable in the lowest grade of other gemstones. These
inclusions, known as jardin or sometimes garden, are expected and even
considered as evidence of the stones authenticity and sometimes an
indication of its origin. The finest emeralds will have a medium green
color, not tending to be too yellowish or blueish, ans gray or black
secondary colors will not be present. The center of the stone, visible
through the table, should be as free of inclusions as possible.
Virtually all emeralds are oiled or resin filled to mask inclusions or
pits that break the surface. This practice has been accepted as normal
for almost 500 years and is not considered an enhancement.
Colombia, considered the world's most important source of emeralds,
produces the biggest and most beautiful emeralds from nearly 150
mining locations. Coscuez mining provides almost 75% of columbias
emeralds from 60 of these locations. Smaller quantities come from
Brazil, Zambia, and Zimbabwe, but these countries are becoming
increasingly important to the market due to the size and quality of
their gemstones. Some sources indicate that Brazil has recently taken
the lead in emerald production. Minor contributions are made to the
emerald market from small deposits in Pakistan, India, Russia,
Afghanistan, Australia, Madagascar, and from North Carolina,
Connecticut, Maine, and New Hampshire in the U.S. Ancient emeralds
were from mines in Egypt with Germany contributing substantially in
the middle ages.
| Composition | Be3Al2(SiO3)6 | Class | Cyclosilicates |
| Specific gravity | 2.67 to 2.78 | Refractive Index | 1.566 to 1.602 |
| Birefringence | 0.005 - 0.008 | Pleochroism | weak |
| Cleavage | poor | Fracture | conchoidal / brittle |
| Luster | vitreous | Transparency | translucent to opaque, rarely transparent |
| Streak | white | Fluorescence | Usually none |
| Crystal system | Hexagonal | Twinning | |
| Hardness | 7.5 - 8.0 | Dispersion | .014 |
| Color | deep green, can have slightly yellowish or blueish tones. Interestingly, emeralds owe their color to small amounts of Chromium oxide (about 3%), This is the same element in the same percentage that gives the ruby its red color. |
| Crystal habit | typically small elongate first order prisms, often with vertical striations and irregular pinacoidal terminations |
| Other | Emerald inclusions are usually indicative of the origin of the stone. Colombian emeralds normally have three phase inclusions consisting of a solid (usually a pyrite crystal), a liquid (salt water) and a gas (usually CO2). South African emeralds have dark needle-like inclusions, stones from India usually have square dark inclusions (biotite) while those from the Ural Mountains in Russia have actinolite needles. |
The name Emerald is from the Greek "smaragdos" for green, through
the Latin word "smaragdus" to Middle English "esmeralde" and from
French "esmeraude". The most ancient mines known were exploited by
Egyptian Pharaohs between 3000 and 1500 B.C. Located near the Red
Sea in Egypt, they gained fame as "Cleopatra's Mines". Lost since
the middle ages and rediscovered in 1818, the mines had been worked
to exhaustion with only a fewpoor quality crystals remaining.
Emeralds have been found in Germany since Roman times, in the
Legbach ravine at Habachtal near Salzburg, but these are no longer
commercially mined. Chibcha Indians mined emeralds in Colombia in
the early 13th century and successive peoples of the region have
continued since. They have been produced artificially since the 1930's
using a process developed by Carroll F. Chatham.
Treasured for nearly 5000 years, the emerald is rich in
superstition, tradition and legend. The emeralds of ancient times
probably referred to a number of distinct species of green stones
including tourmaline tsavorite garnets, and peridot. Emeralds
supposedly sooth the eyes, preserves chastity, cures dysentery,
prevents epilepsy, drives away evil spirits, gives its owner the gift
of eloquence and quicken intelligence as well as the heart. It's color
implies harmony, love of nature and a primeval joy of life. The Incas
had an emerald goddess to which they sacrificed their children.
Legends tell of a Spanish settler who discovered a fine emerald
embedded in the hoof of his lame horse. When it was back-tracked, it
led to the rediscovery of the now famous Muzo mine which had been kept
secret through years of torture of the local Indians by Spanish
conquistadors trying to learn of the source of this beautiful stone.
Treasure hunters seeking wrecks of Spanish galleons are occasionally
rewarded by the discovery of emeralds lost by the conquistadors long ago.
Colombian emeralds have been the source of great wealth and great
sorrow for the people of the region. Beginning with the torture and
murder of the local Indians by the Spanish conquistadors trying to
force them to reveal the location of emerald mines, to the murder of
over 900 people in the region in 1972 due to disputes over the control
of emerald bearing regions. Many corporations, groups and government
agencies have controlled the emerald mines over the years, but each of
them had their share of theft, murder and corruption. With the
murderous outbreak of 1972 the Colombian government closed down the
mines and negotiated leases with private businessmen to run the
mines. Although this has stabilized the region and reduced the
violence, a good percentage of emeralds are mined illegally, or have
strong connections to the drug cartels.
Although not resulting in the violence found in Colombia, emerald
mining in the US has had it's share of tragedy, including a bitter
lawsuit in the mid 1980's. An emerald crystal of record perportions
was discovered near Hidden, North Carolina. The dispute was resolved
when one of the parties cut the 14 inch crystal in half, destroying
the value of this priceless gem.
