Ancient alchemists, including Isaac Newton, had one desperate ambition: transform a lesser material into precious gold. According to this 1948 article, U.S. "wizards" (also known as radiochemists) in Tennessee finally succeeded in manufacturing synthetic, radioactive gold using cyclotrons and atomic piles, though the treasure tended to disappear rapidly.
PopSci also published Emilio Segre's isotope chart, which resembled a "giant crossword puzzle." The discovery of isotopes meant that familiar elements could have unexpected properties. Even "well-behaved elements like iron and sulphur may turn into something else while your back is turned!"
Read the full story in U.S. Alchemists Make Gold