Tin's pairing with Jupiter is consistently attested across the alchemical tradition, and its symbol, a crescent set above a cross, is identical to the astrological glyph for Jupiter, though the underlying reasoning behind this particular metal-planet pairing is less immediately intuitive than iron's link to Mars or gold's to the Sun, and historians of alchemy generally treat the seven metal, seven planet correspondence as a systematic, largely a priori scheme, seven metals matched to seven known planets in a fixed traditional order, rather than one where every individual pairing needs its own separately motivated justification.
Tin's comparative softness, its position in the middle of the traditional hierarchy of metallic perfection between the base heaviness of lead and the refined stability of gold, was read by some alchemical writers as reflecting Jupiter's own traditionally benevolent, moderate astrological character, a symbolic reading applied after the fact to a pairing whose original basis may simply have been the need to complete a matched set of seven. Tin's own tin pest transformation, though unrelated to its planetary symbolism, offers a fitting closing irony: a metal associated with Jupiter's supposed benevolent stability turns out, under the right cold conditions, to be one of the least structurally stable of the seven classical metals.