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The Metal: Gold |
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Types Of Gold |
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Throughout Ancient America, there were two predominant type of gold alloy used. The
first, and very common is high quality, 10 to 18kt gold. The other is
a low quality gold alloy known as "Tumbaga". |
An example of cast gold. |
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In the case of Tumbaga, after
the casting was completed, the surface was treated with plant acids to leach
away the copper leaving a thin film of higher grade gold that was then
burnished to a bright color. Tumbaga was rugged, but suffers more from
the effects of burial and exposure to reactive ground waters, typically
resulting in some metal loss and a fair amount of spalling of the surface
gold revealing the underlying coppery core. Frequently copper salt
plugging of the finer details also occurs. (see below) |
An example of Tumbaga |
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Aging Gold |
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 Most pieces displayed here do not have precise contextual
information, nor are they scientifically dated. Therefore, most fall
into the general range of from 500 CE (AD) to prior to the arrival of the
Spanish (approximately 1500 CE). Only where an actual date of the item
can be established through context (location and strata found) or through
dating will the date/age of the item be displayed.
It is rare that gold pieces can be accurately dated.
This is typically done by two means: contextual dating - where the
piece was found; or by scientific dating - based upon the material contained
in/on the piece itself.
In the case of
contextual dating, we rely on the location of the find. When
excavating a site, gold pieces can be found, and soil from the ground level
can be dated indicating the date of the gold piece. This is generally
reliable, except where the design of the piece may strongly contradict the
ground context - this occurs when an older piece was found, used, and
reburied some substantial time after if was originally created.
In the case of
materials dating,
some material in or
on the piece can be used to date the item. In this case, the process
is destructive. That is some part of the material must be destroyed to
yield the dating information. In some cases, poorly cleaned pieces may
still have organic material or soil adhering to the piece, that can be
removed and used as the sample for dating. In other cases , where a
clay core was used, the original clay core if still inside the hollow body
of the piece can be used. A sample of the clay can be extracted from
the inside of the piece with a minor intrusion, and submitted for
laboratory thermoluminescence analysis to determine the age of the casting.
In the case of organic materials, carbon dating is also done.
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Casting Gold |
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 Like
wax-resist ceramics, gold working seems to have begun in Peru, perhaps as
early as 1500 B.C. Knowledge of casting, hammering, repoussé, and inlay
spread from Peru and possibly Colombia northward, passing through Panama and
Costa Rica on its way to Mesoamerica, where it finally arrived in the 10th
century A.D. These same methods are still in use today for the making
of fine jewelry.
The lost wax
method consisted of making a wax sculpture of the item, then covering it in
a ceramic outer cover, then melting and pouring out the original wax.
The gold is then poured into the ceramic and cooled. The ceramic is
then removed leaving only the gold. Very complex figures can be
created using this simple method.
The wax was typically bee's
wax warmed to be pliable, then carved into the desired shape, then cooled in
a river or water to harden and hold it's shape. The clay/ceramic used
to form the mold is itself wet and soft, which helps keep the wax hard, and
also allowing it to better mold to the shape of the wax. Since it is
more difficult to maintain the integrity of larger pieces, often the
appendages are made separately. This allows for the fine details to be
created without worrying about the model being maimed or destroyed.
with separate pieces, a drop or two of molten gold can be used to solder or
join pieces together.
Once the wax is fully coated
with clay/ceramic, it is then "fired" (hardened) in some form of a kiln or
fire - this hardens the ceramic, and liquefies the wax. After the mold
is hard, the wax has either burned away, or can be poured out of the mold,
leaving it ready for the molten metal. This leaves a hollow where the
wax was inside the ceramic. After the ceramic is cooled and ready for
use. The metal is then poured into the mold, and either temper cool by
immersing it in water, or allowed to air cool. After which, the
ceramic is broken off the gold piece. Thus both the original design in
wax, and the mold are both destroyed in the process. So each and every
piece is an original and unique.
Click here to visually see how this process is done.
A variation on the lost wax
method is a half cast, where the cast is open and reusable (like an ice
tray). This allows repeated use of the mold (under ideal conditions),
but does not permit complex designs, since the design must be removable
without breaking the mold. In fact, the author once used a variation
on this process: caved a pattern from wood, then used plain mud (as well as
raw clay) as a mold - since the pattern remained intact, this was an easily
repeatable production process. While there is no factual proof that
this latter process was ever used in Precolumbian times, it is nonetheless
workable for simple designs. Enigmatic stone hollows found throughout
the region may also have been used in this fashion.
Also visit
our Gold Information & Glossary Page » |
Front View Of Lost Wax Cast Piece
Rear View Of Lost Wax Cast Piece
A Maya Gold Pottery Cast
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Metalworking |
Repoussé or repoussage
is a
metalworking technique in which a
malleable metal
(such as gold leaf) is ornamented or shaped by
hammering from the reverse side.
Chasing is the opposite technique to
repoussé, and the two are used in conjunction to create a
finished piece.
Whilst repoussé is used to work on the
reverse of the metal to form a raised design on the front, chasing
is used to refine the design on the front of the work by sinking the
metal. The term chasing is derived from the noun "chase", which
refers to a groove, furrow, channel or indentation. The adjectival
form is "chased work".
The techniques of repoussé and chasing
utilize the
plasticity quality of metal, forming shapes by degrees. There is
no loss of metal in the process, as it is stretched locally and the
surface remains continuous. The process is relatively slow, but a
maximum of form is achieved, with one continuous surface of sheet
metal of essentially the same thickness. Direct contact of the tools
used is usually visible in the result.
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Tumbaga Gold |
 Tumbaga was
the name given by Spaniards to a non-specific alloy of gold and
copper which they found in widespread use in Pre-columbian
Mesoamerica.
Tumbaga is an alloy comprised mostly of gold and copper. It has a
significantly lower melting point than gold or copper alone. It is
harder than copper, but maintains malleability after being pounded.
Tumbaga can be treated with a simple acid, like citric acid, to
dissolve copper off the surface. What remains is a shiny layer of
23-karat gold on top of a harder, more durable copper-gold alloy
sheet
Use In The Americas:
Tumbaga was widely used by the pre-Columbian cultures of central
America to make religious objects. Like most gold alloys, tumbaga
was versatile and could be cast, drawn, hammered, gilded, soldered,
welded, plated, hardened, annealed, polished, engraved, embossed,
and inlaid.
The proportion of gold to copper in artifacts varies wildly; items
have been found with as much as 97% gold while others instead
contain 97% copper. Some tumbaga has also been found to be comprised
of metals besides gold and copper, up to 18% of the total mass of
the tumbaga.
In 1992, approximately 200 tumbaga bars were recovered in wreckage
off Grand Bahama Island. They were composed of gold, copper, and
silver plundered by the Spaniards during the conquests of Cortez and
Pizarro and hastily melted into bars of tumbaga for transport across
the Atlantic. Because all the metals that reached Europe were melted
back into their constituent metals in Spain, the bars found in the
shipwreck are the only known bars of tumbaga that remain.
It is believed that the technology for mining and working metals
migrated southward from the higher cultures of Mexico down along
both the Pacific and Gulf/Caribbean coasts to Costa Rica & Panama.
Myths:
Some Mormon scholars suggest that the Golden Plates from which the
Book of Mormon was allegedly translated may have been made from
tumbaga.
Orichalcum, the legendary metal of the island of Atlantis, is
commonly held to have been a gold-copper alloy, thus fitting the
same description.
One obscure reference indicates that the origin of Tumbaga,
originates from the mythical landing point of the Nahuat speaking
peoples on the west coast of modern day Mexico. That landing point,
and resultant settlement were alleged to have been name Aztlantla
(now referred to as Aztlan). That settlement was created from
concentric ring islands (said to resemble their homeland) in the
mangrove swamps near modern Mazatlan.
It is believed that the technology for mining and working metals
then migrated southward along both the Pacific and Gulf/Caribbean
coasts
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An example of Tumbaga
Shows heavy copper corrosion
An example of poor quality Tumbaga
little gold in alloy
click photos
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enlarge |
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A History Of
Ancient American Gold |
"The quantity of gold they have is endless …"
—Marco Polo
During the earliest years of
European
expansion onto the American continents, the search for gold was one of
the driving factors in the exploration and colonization of the vast lands.
The existence of the two great continents was unknown in Europe until the
fateful day in October 1492 when Christopher Columbus landed on an "island
in the Indies," having miscalculated the circumference of the globe by about
25 percent. Columbus, a master mariner then in the service of Spain, and an
avid reader, was searching for Cipangu (Japan), the island of "endless
gold," about which he had read with great excitement in Marco Polo's
Travels. Convinced that fabled Cipangu was not far from the small island
on which he had landed, Columbus went ashore and, unfurling royal standards,
claimed it for his sponsors, King Ferdinand and Queen Isabella of
Spain—thereby initiating what would become the vast Spanish empire in
America.Christopher Columbus in the
Caribbean
The island's inhabitants greeted Columbus with curiosity. According to the
journal he wrote about his voyage, he found them to be handsome and very
gentle. Some wore little pieces of gold suspended from holes in their noses.
Intrigued by these ornaments, Columbus attempted to learn more about the
availability and quantity of the gold. He made the first inquiries into
local sources, instigating the search for precious American metals that
would be a major obsession of conquerors, colonists, travelers, and
opportunists for centuries. As he sailed among the island of the Indies
searching for the wealthy courts of Asia, Columbus asked repeatedly about
gold. When, on Christmas Eve in a calm sea, his ship, the Santa Maria,
ran aground, he thought he found the evidence he was seeking.
The Santa Maria was firmly stuck on the banks of an island that
Columbus named Española (Hispanola). While the crew attended to the damaged
vessel, local people arrived to trade bits of gold for brass hawks' bells
carried by the sailors. Columbus was so cheered at the sight of the gold
that the island chieftain—who wished to see him even more pleased—told the
dismayed mariner that the precious metal could be found in abundance nearby
and gave him an impressive mask inset with large pieces of gold. This
evidence, and the prospect of much more, led Columbus to believe that the
shipwreck had been providential. To Columbus, driven by the search for the
wealth that would be a tangible indicator of a successful voyage, the
discovery of vast quantities of gold would represent both a personal reward
and a vindication of his vision.
The News in Europe
En route to Spain, Columbus wrote to the king and queen telling them of the
newfound lands across the western sea and the rich islands of the Indies. In
a letter amazingly brief for the magnitude of its contents, he reported that
he had claimed the island for the Spanish sovereigns. He told of the
innumerable peoples he had encountered; of birds, trees, exotic fruits, and
plants; of the rivers that contained gold; and of mines for gold and other
metals. This astonishing letter was eagerly received in Spain and initially
published in Latin in the spring of 1493. By the end of the fifteenth
century, it had been printed in numerous editions in various cities in
Europe, where the news was disseminated quickly.
The search for gold became a predictable part of the European experience in
the Americas from Columbus's day onward, despite the fact that during his
second voyage he learned that there was no mine on Española. Gold mines were
rare in the Americas, as the precious metal was chiefly taken from rivers
and streams. Yet the notion of accessibility to great riches endured, and
the search for them was compulsively pursued. Rumors of gold brought Hernán
Cortés and several hundred men to Mexico in 1519. Making his much-noted trek
into the interior from the Gulf Coast, Cortés heard, and followed,
tantalizing tales of a powerful ruler and immense wealth.
Aztec Mexico
The ruler was the Aztec king Motecuhzoma (Montezuma II), whose capital city
was
Tenochtitlan, in the central highlands. Wishing to prevent the arrival
of the Spaniards in his city, he sent emissaries to Cortés with extravagant
gifts: a gold disk the size of a cartwheel; a silver disk of the same size;
diadems, earrings, and figures of gold and mosaic; armbands of silver;
multistrand necklaces with hundreds of gold beads and red and green stone;
hollow gold ornaments cast in complex shapes; shields and helmets covered in
turquoise mosaic; brilliant feather fans and headpieces; elaborate garments
and costumes—all were among the exotic and wonderfully strange objects the
Spaniards received as tribute.
Cortés sent the gifts to Spain, and in the spring of 1520 the treasure was
presented to the newly elected
Holy Roman
Emperor, Charles V, king of Spain. Great excitement greeted the wondrous
objects and learned men commented upon them. No opinion is better known or
valued than that of
Albrecht Dürer,
who saw the treasure in Brussels in August 1521. In the diary of his journey
to the Netherlands (1520–21), he wrote of the gifts "brought to the King
from the new golden land: a whole golden sun, a whole yard wide, likewise a
whole silver moon, also equally big, likewise two chambers full of …
wonderful things for various uses, that are much more beautiful to behold
than things of which miracles are made."
Unfortunately, such learned interest and appreciation were of modest
duration, and none of the works from this hoard is known to have survived.
The cartwheels of gold and silver and all the pieces of precious metal were
melted down, and objects of more ephemeral materials discarded. The same
fate befell the royal treasury of the Aztecs. Cortés, far from being
deterred by the rich presents he was offered, marched on to Tenochtitlan,
where he imprisoned Motecuhzoma and sacked the treasury. Much of the
contents went to Spain, but only a few of the most exceptional pieces
reached there in the shapes made by Mexican artisans; the rest arrived as
bullion.
Inka Peru
The lure of the golden cities continued, and in the mid-1520s another
adventurer, Francisco Pizarro, sailing along the Pacific coast of Colombia,
encountered communities with abundant gold and silver. Wishing to gain
control of the region for himself, Pizarro hurried to Spain and successfully
petitioned to become governor in 1529. Shortly thereafter he set out for
Inka Peru, the richest of all the American kingdoms where temple walls were
covered with gold and golden pots held golden treasure. Precious metals had
been worked in Peru for some 3,000 years before Pizarro arrived. Personal
adornment of gold—diadems, ear ornaments, pectorals—of great size and
substance were produced during the first millennium, and by the sixteenth
century gold and silver creations were highly imaginative and included,
according to the accounts of Spanish chroniclers, miniature gardens made
entirely of gold. The use of precious metals was restricted to the Inka
nobility, concentrating power and wealth in royal hands. Pizarro gained
access to this fortune in 1532, when he and his men ambushed the Inka ruler,
Atawalpa (Atahuallpa), and held him for ransom.
The ransom was immense. In an effort to gain his freedom, Atawalpa filled a
large room with gold and two rooms with silver. The rooms were stacked high
with tubs of the metal, platelike tiles of gold, and many other objects. Yet
this treasure did not buy freedom for Atawalpa or his kingdom. The country
was stripped of its wealth, and the rich temple fixtures, a well as the
precious gardens with earth of gold granules, gold cornstalks, and gold
figures of men and llamas, were rendered into neat bars. Forty years after
Christopher Columbus saw modest bits of gold among the peoples of Española,
the dream of incredibly rich royal courts and seemingly endless supplies of
gold had come true.
Source:
Julie Jones; Department of Arts of Africa, Oceania, and
the Americas, The Metropolitan Museum
of Art
Citation for the above: Jones, Julie. "Gold of the Indies". In
Timeline of Art History. New York: The Metropolitan Museum of Art,
2000–.
http://www.metmuseum.org/toah/hd/ingd/hd_ingd.htm (October
2002)
Suggested Further Reading: Jones, Julie, and Heidi King. "Gold of the
Americas." Metropolitan Museum of Art Bulletin 59 (Spring 2002).
Jones, Julie, ed. The Art of Precolumbian Gold: The Jan Mitchell
Collection. Exhibition catalogue. New York: The Metropolitan Museum
of Art, 1985.
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Tumbaga was
the name given by Spaniards to a non-specific alloy of gold and
copper which they found in widespread use in Pre-columbian
Mesoamerica.
