Medieval alchemists assigned planetary symbols to metals: Gold (Sun ☉), Silver (Moon ☽), Mercury (Mercury ☿), Copper (Venus ♀), Iron (Mars ♂), Tin (Jupiter ♃), and Lead (Saturn ♄).
These associations weren't arbitrary - they were based on observed properties. Gold's brilliance matched the Sun, silver's reflectivity matched the Moon, and Mercury's fluidity matched the swift planet.
Modern chemistry's symbols and element classifications evolved directly from these alchemical-astrological foundations.