But, also, they were literally trying to turn lead into gold.

(The term 'alchemy' covers a broad swath of various people in various times, with various beliefs and practices ranging in the spiritual, metaphysical, psuedo-scientific, and scientific realms. For some, yes, turning lead into gold was pure allegory. For others, it was an actual literal goal and they hoped to become rich that way. And for some, it was both at the same time -- pursuing both spiritual enlightenment and economic enrichment in the exact same process. It's further complicated by the fact that many of them were persecuted in their time and/or feared non-alchemists stealing the recipes and techniques they had discovered, so even when they were writing down actual legitimate scientific findings and real chemistry, they often did so in fantastical, allegorical terms that only someone steeped in alchemical lore might be able to decipher.)