https://emuseum.cornell.edu/internal/media/dispatcher/79186/fullNose ringca. 600–15007/8 × 13/16 × 3/8 inches (2.2 × 2 × 1 cm)Gold-copper alloy (tumbaga)Gift of Thomas Carroll, PhD 19512006.070.2950Manteno nose ring made from Tumbaga, a copper-gold alloy. Extensive green oxidation over the surface of the nose ring, with some gold visible on the surface only on one side, indicates that this piece may be mostly copper, with gold largely only on the surface. Sometimes the process of depletion gilding-the application of an acid to the surface to remove everything except gold-- was used on tumbaga objects to increase the golden color of the surface.
Tumbaga is formed from a mixture of copper and gold, and usually also contains some silver. Copper alloys differ in the amounts of other metals (such as gold, silver, and arsenic) present, depending on location and time period. Silver was rare in Ecuador and is generally found in copper and gold objects only as a naturally occurring impurity rather than as an intentionally added component; however, metal artifacts with the highest concentrations of gold and silver appear to have been high-status items. Platinum is known to have been used to plate precious metal objects in prehistoric Ecuador due to the rarity of silver, even though the extremely high melting point of platinum makes its use technically difficult.
Very similar to Manteno copper nose rings 2006.070.293 and 2006.070.294.
Metalwork20281140503Unidentified artistManteno (Ecuador)2006.070.295_d0561_019