Gold was worked by essentially the same techniques across the ancient, medieval and early modern worlds: panned or mined as native metal, refined by cupellation or by dissolving away baser metals with acids that left gold untouched, and worked by hammering, since gold's extreme malleability allows it to be beaten into sheets far thinner than paper without cracking, a property no other common metal matches. Alchemists valued gold above all for what it would not do: it does not tarnish in air, does not rust, and resists nearly every acid except the specially formulated aqua regia, a stability that, within the alchemical framework, was read as evidence of gold's superior chemical maturity, the state every base metal was theoretically capable of reaching given the right process.
That theoretical belief drove the entire practical program of transmutational alchemy: if lead, tin, iron, copper and the other base metals were simply less perfected forms of the same underlying prime matter that gold represented in its finished state, then a sufficiently refined process, the philosophers' stone chief among the hoped for agents, ought to be able to complete that maturation directly, turning base metal into gold. No such process has ever been verified to work, and modern chemistry explains gold's stability, and its complete chemical independence from lead, tin or any other base metal, through nuclear and electronic structure that no chemical process, only a nuclear one entirely beyond alchemical reach, could ever alter.