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Atocha
Emeralds Help to Shed New Light on History of Gem Trade
Atocha Emeralds Help
to Shed New Light on History of Gem Trade
Corey Malcom
March 2000
The emeralds recovered from the wreck of Nuestra Seņora
de Atocha have recently played a decisive role in
determining the origins for many renowned jewels around
the world. A team of French and Colombian geologists
worked to determine the specific markers revealing the
source of emeralds. They found the levels of oxygen
isotopes in the crystals were excellent source-point
indicators, and often made the gem traceable to an
individual mine. By blasting each emerald with an cesium
ion beam, they were able to effectively dislodge the
oxygen ions. These were then collected and analyzed for
specific values. The measurements allowed the
researchers to examine emeralds from collections around
the world, and re-evaluate their supposed origins. An
Atocha emerald was utilized as a
test subject in the analysis, and confirmed the oxygen
isotope value for a Colombian origin. This work is
presented in the January 28, 2000 issue of the journal
Science.
The standard theory has been that all gem-quality
emeralds in the ancient world came from two sources - in
Austria and Egypt. The analysis changed this. Some of
the gems came from previously unrecognized sources in
Pakistan and Afghanistan. Most surprisingly, many
emeralds - long thought to have been
"ancient"- were actually mined in Colombia,
and brought to the Old World via the Spanish fleets in
the 16th and 17th centuries.
When Colombian emeralds were discovered by the Spanish
in 1536, during conquest of South America, they were
highly prized. The mines quickly came under Spanish
authority, adding to an almost unbelievable array of New
World treasures controlled by that nation. The gems from
this region have long been considered the finest in the
world; a quality that was recognized early on, as
evidenced by their rapid spread across the globe so
shortly after their discovery. The emeralds recovered
from the Atocha provide solid archaeological evidence
for the existence of this early trade. To date, just
under 6,000 uncut, "raw" Colombian gems have
been recovered from the wreck, as well as those that
were already cut, polished, and mounted into gold
settings. Perhaps if these Atocha jewels were not lost,
and had reached their intended destination, they would
have simply been traded across Europe and Asia, and then
assumed by gemologists of today to have been much older.
For
a printable version in Acrobat PDF format, please click
here.
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archaeology for more
information.
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