Finally, someone has found a good use for gold other than ridiculously overpriced a/v cables.
This is why you're being downvoted. Check Wikipedia before commenting next time.
Cupellation plus touchstones are adequate both to refine electrum and to destructively measure the quantity of gold in the electrum. By Roman times, we were smelting electrum with salt to separate out the gold by chloriding the silver, and the Lydians may have been doing that already by the fifth century BCE, when they started debasing their electrum coins with extra silver.
This sounds kind of stupid, since at this point we're used to being able to purify and quantify all kinds of materials, but in fact these attributes made gold and silver unique among rare elements for centuries.
(...and jewelry)