Tumbaga was used in pre-Columbian times (roughly from 600 A.D. on)
from Central America to Peru and Chile as a generic term for any
combination of gold and copper. It could range from 95% copper to
95% gold, although tumbaga or guanin gold was usually made by adding
10 to 30% copper to gold. Tumbaga usually contains 5 to 10% silver as
well, which occurred naturally in the gold and wasn’t intentionally
added. That�s the definition given in “Sweat of the Sun, Tears of
the Moon” and another source I have.
There were several reasons tumbaga was popular. A primary one is
that 70% gold/30%copper will melt at around 800 C., much lower than
gold or copper separately. That’s important because melts were done
in large clay pots using a team of men huffing on blowpipes.
(There�s an amazing Moche clay urn I’ve seen that shows this
procedure in detail). Molten metal then flowed from a hole in the
bottom of the vessel into open molds made from stone or clay. These
molds have been found archaeologically from Mexico to Chile.
The lost wax casting techniques of these peoples were very
sophisticated as well. They routinely cast hollow objects and bimetal
part silver-part gold objects using complex one-time molds made of
ground charcoal, sand and clay. Depletion gilding was routinely used
to decorate the surfaces of objects made from low-gold alloys. The
amount of gold used in tumbaga depended on the metal�s availability.
Objects from gold-rich areas like Calima and Tolima in Colombia, for
instance, were large and contained purer gold while most pieces from
the Muisca and Tairona regions were smaller, less pure and depended
on gilding for appearance.
Tumbaga had another interesting use as well. Some cultures like the
Moche placed small tumbaga ingots in the mouths of their high-ranking
dead prior to burial. I�ve encountered this same ritual using
various metals while studying the burial practices of several other
ancient cultures around the world but am not clear on its
In the bibliography of “Sweat of the Sun, Tears of the Moon,” the
following sources are listed:
Coggins, Clemency Chase. “Artifacts from the Cenote of Sacrifice
Chichen Itza, Yucatan.” Ed. Clemency Chase Coggins Vol. 10/No. 3
Cambridge, The President and Fellows at Harvard College, 1992.
Jones, Julie. “The Art of Precolombian Gold: The Jan Mitchell
Collection.” Ed. Julie Jones. Boston Little, Brown and Company,
Nottebohm, Karl-Heinz. “A Second Tlaloc Gold Plaque from Guatemala.
Notes on Middle American Archaeology and Ethnography.” Vol. 2
Numbers 31=60. New York AMS Press, 1969.
Weaver, Muriel Porter. “The Aztecs, Maya, and their Predecessors;
Archaeology of Mesoamerica.” Third Ed. San Diego, Academic Press,
I have a wonderfully detailed article, “Gold of El Dorado:
Technology of Ancient Colombian Gold” by Clemencia Plazas and Ana
Maria Falchettie de Saenz that appeared in �Natural History�
(November 1979, Vol. 88, No. 9, pp. 36-46).
If it�s still in print, “Royal Tombs of Sipan” by Walter Alva and
Christopher B. Donnan is a beautifully produced and illustrated
showcase of Moche gold and silver work. It was published in
conjunction with a traveling exhibition from UCLA�s Fowler Museum.
The ISBN of my softbound (expensive enough!) is 0-930741-30-7.