And trickles of silver and gold, also copper and lead, would stream And pool in the earth’s hollows.
When cooled, men saw the gleam Of their glinting colours in the soil, and drawn to what they’d found – The shiny smoothness of the nuggets – pried them from the ground,
And saw these bore the shapes of the depressions where they lay.
Then this drove home that they could shape the nuggets in this way – Melting them down and pouring them into any mould they made.
Lucretius, De Rerum Natura, Book 5, lines 1255–61