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I've looked into this briefly and from what I've understood, the kind of copper that's used to make electric copper wire is generally of a high purity (well above 99%). What are some other household objects that may be primarily composed of highly pure/unalloyed metals?

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    $\begingroup$ Depends on your threshold for purity. Some computers have shells made of aluminium (some suggest the alloy used by Apple is designated 6061 which is >98% Al). Al foil is purer than this. Some batteries may contain relatively pure lithium, some small cast objects might be largely zinc, jewellery can be silver, platinum or gold. $\endgroup$
    – matt_black
    May 1, 2023 at 10:26

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As you mention, electrolytic copper, used in electronics, is >99.9% Cu.

Household aluminum foil is ~99.8% Al, though it migh be alloyed for greater strength.

You might find fairly pure lead used for plumbing or ammunition, but it is often alloyed to make it harder. A very rough purity test can be performed with different grade hardness pencils.

Fairly pure tin is used for specialty solder, e.g., for items that come into food contact. Ordinary solders were Sn/Pb alloys, where lead has been replaced with Bi or other lower melting point metal now.

Mercury of ~99.9% purity might be found in old thermometers and "silent" electric switches.

Tungsten wire in lamp and valve (radio tube) filaments was fairly pure, but is now "doped" with oxides, including thorium, to make it stiffer and increase electron emission.

One might have a titanium tooth implant, or tantalum joint implant, but I don't know the purity of those materials.

Jewelry made of pure Au, Ag or other such metal is rare, since they would lose shape quickly, even take fingerprint impressions. Perhaps precolumbian New World artifacts? Stronger Pt might be used, but is difficult to find >90% pure. One might find a tiny amount of pure Au in gold lettering, or in the radiation emitter in a smoke alarm. Yes, a radio-emitter is added to the gold foil, but <<0.1%.

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  • $\begingroup$ Gold jewelry is often alloyed with base metals for wearability, so we see things like 14 karat instead of tge pure 24 karat. $\endgroup$ May 2, 2023 at 1:54
  • $\begingroup$ @OscarLanzi, exactly, which is why precolumbian ornaments were mentioned, because they might not have been alloyed. BTW, I've used gold so soft that pressing (my somewhat calloused) finger into it left an impression! $\endgroup$ May 2, 2023 at 15:39

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