So, how did the acquisition of metal work in medieval times?

[tarchon]

So people wouldn't be likely to putter around trying to discover new metals.

I don't think it follows that people wouldn't try to smelt different rocks because they already knew seven different metals. It goes without saying that if people hadn't gone around trying to smelt different rocks, they wouldn't have known how to smelt any metals, let alone six. The problem with ores is that even if you know what the element copper is, you can't look at a rock and say "oh, that's obviously a copper ore." For one thing, there are several usable copper ores, e.g. azurite and malachite, and, as any geology student can tell you, even a hunk of malachite from mine X may or may not look like a hunk of malachite from mine Y. Pliny just didn't have scratch plates and diffractometers, which is why half the time when Pliny talks about some type of stone, we don't have the faintest idea what he really meant. Most rocks and minerals, even many metals, were identified strongly with their place of origin rather than being recognized as a particular substance that could occur anywhere. Thus, it stands to reason that, not being able to tell whether a given rock was a metal-bearing ore by any other known means, the ancients must have identifed ore bodies by means of practical experiments.

 

[mythusmage]

Platinum was unknown, but that's most likely due to the only deposits being in the New World.

Actually, platinum is mined in Siberia, but its discovery there did come well after the 14th century.

BTW, zinc and tin are often found together. Matter of fact, many of the bronze items from antiquity had more zinc than tin in them.

Silver, on the other hand, is often found in association with lead, nickel, and cobalt. Nickel as a matter of fact was originally known as nickel silver, or Devil's Silver. Cobalt comes from the German "Kobold". Said to be the mischievous mining spirits who would steal the silver from silver ore during processing, leaving behind the 'worthless' white metal we now call cobalt.

Many of the metals we know of today we learned of when we learned how to tell them apart from the classical metals.