Gold extraction in the ancient Andes
mike ruggeri
A team of geologists and archaeologists have found that ancient pre-
Inca cultures may have known how to refine gold with mercury
amalgamation. This is still used today to distill almost pure gold and
silver from ore. The Romans did this but the technique was not used in
Europe till the 12th century. The team analyzed residual mercury
levels in 7 samples from Peru and Columbia. 3 of the samples were from
the Sican culture (750-1375 CE). They found signs of amalgamation
similar to the technique used today in gold foil. The report on this
finding was given at the Geological Society of America's annual
meeting.
There is some criticism of the findings. Almost all Sican gold was
looted, so the context of this gold is uncertain. Izumi Shimada, head
of the Sican Archaeological Project, said that the cinnabar used to
cover the dead elite contains a lot of mercury-sulfur which could have
contaminated the samples. The team replied that they did carefully
remove the cinnabar and the tests revealed consistent measurements and
not random variations between samples which would have been the case
if there had been contamination.
Science Now has the story here;
http://sciencenow.sciencemag.org/cgi/content/full/2009/1020/2
A tiny URL;
http://tiny.cc/nddXy
Mike Ruggeri
Mike Ruggeri's Andean Archaeology News and Links
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