Lead's pairing with Saturn is one of the most thoroughly developed correspondences in the entire alchemical tradition, and its symbol, most often drawn as a cross set above a crescent though also rendered in other traditions as a stylized sickle or scythe, is identical to the astrological glyph for Saturn, itself often associated with a sickle or scythe through Saturn's classical mythological identity as Cronus, the Greek god who wielded exactly such a blade.
Lead's position as the heaviest, dullest, slowest to melt among the readily workable classical metals matched neatly onto Saturn's own traditional astrological character as the slowest moving visible planet, associated with heaviness, restriction, old age and time itself, a correspondence historians of alchemy including Lawrence Principe treat as one of the clearest cases where a metal's genuinely observable physical properties, density and dullness chief among them, lined up coherently with the assigned planet's independently established symbolic character, rather than the pairing resting on an arbitrary or purely traditional assignment alone. Lead's low position in the metallic hierarchy did not stop it from being genuinely useful and widely traded in its own right, a reminder that alchemical rank and practical economic importance were two entirely separate measures that did not always move together.