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Wikipedia states that ancient Peruvian metalsmiths applied gold with electroplating, citing a 1979 article in The Journal of The Minerals, Metals & Materials Society. I'm not familiar enough with this journal or academia to assess whether the claim is solid, or if later research confirmed or refuted it, but I am skeptical; what would be the source of charge? Why would such a valuable technique be abandoned?

Similar: Did Iraq have the use of electricity 5000 years ago?.

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  • +1 An article by the American Institute for Conservation, "A review of gilding techniques in South America" makes a similar claim: "The remarkable development of electrochemical replacement plating of gold alloys over copper, without the use of a battery, began to be used extensively along the North Coast of Peru, during the Moche period" (100 AD to 800 AD) Jan 18, 2016 at 9:50
  • Note that this technology probably wasn't quite as valuable to ancient Peruvians as it is to modern engineering - copper and silver aren't quite as vulnerable to corrosion as ferrous metals, and gold-plating isn't useful for mechanical toughening. So it is probable that this treatment was primarily cosmetic. Jun 29, 2023 at 3:56

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Yes, possibly.

While we associate electroplating with a bench-top current source, it is also possible to use an aqueous solution of a gold compound, the work-piece, a piece of pyrite and one wire to create what is basically a very bad battery that has been short-circuited. The solution being the electrolyte, the (already copper-plated) work piece and the pyrite being the two electrodes. The wire short circuits the battery, thereby leading to the (electrochemical) deposition of the gold.

The whole process also works without the wire, but to a far lesser degree. Thus, an accidental development from the no-wire method to the wire-method is possible without knowledge of electrochemistry.

For example, we can speculate that someone may have tried the wire-less method first (dip piece by, e.g. dangling from plant fibre) and observe poor results. Later they may have accidentally dipped two pieces (one copper, one pyrite) now attached to a wire. The copper one would have better results, but the pyrite would be pitted and not gold-plated. From that, they may try one work piece connected to a disposable pyrite lump to get better results.

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  • Given that wires can be (and usually are) made of copper, wouldn't simply allowing the copper and pyrite pieces to touch each other effectively do the same thing? (Think of it as either a zero-length wire, or perhaps as one end of the copper object being long and thin and acting as the wire.) Jun 29, 2023 at 20:08
  • @RayButterworth you are correct - that should also work. Maybe even better because a copper wire would also act as an electrode, in that solution, and thereby reap some gold that could otherwise go to the piece
    – bukwyrm
    Jun 30, 2023 at 5:15
  • Also, isn't pyrite known as fools gold, because it contains no gold? Jun 30, 2023 at 12:41
  • @RayButterworth the Pyrite was chosen for its availability and its electrochemical properties. The gold that is later found on the piece comes from the solution.
    – bukwyrm
    Jun 30, 2023 at 12:53

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