system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did humans learn to extract metal from rocks?

This is something that has always perplexed me. How the hell did our ancestors learn that putting certain types of rocks in 2000 degree furnaces would yield a useful material for weapons and tools?
gpt
Certain metals like gold, small amounts of iron, etc. can be found in their natural form without smelting.  As time went one our ancestors learned that other metals could be extracted from rocks by heating them.  Not all metals require insane temperatures to smelt either.  Some of the early attempts could also have been accidental as hearth stones that contained ore were heated and we observed that metal came out of them.