Silver is the second of the metals that can be found native, and the second in the classical hierarchy, but the great ancient supply did not come from nuggets. It came from cupellation, the roasting of lead ores in a bone-ash hearth until the lead oxidises away and the silver is left behind. That process ties silver and lead together in the workshop as closely as the planetary scheme separates them, and it is worth holding in mind whenever the two are set at opposite ends of a table of correspondences.
Silver tarnishes where gold does not. The black film that forms on it in air is silver sulphide, and that plain chemical fact underlies a long habit of reading silver as the pure metal that is nonetheless susceptible, needing attention where gold needs none.
Its ritual life in Europe is largely lunar and largely nocturnal. Silver vessels, silver mirrors and silver coins recur in folk practice as the material that meets what belongs to the other side, and the silver bullet of nineteenth-century story belongs to that pattern rather than to any older text. In the Greek world the silver of the Laurion mines paid for the Athenian fleet, a reminder that the metals of the planetary scheme were strategic commodities and that the people who assigned their meanings knew exactly what they were worth.
Alchemically silver is luna, one rung below gold, and the albedo, the whitening, takes its name and its imagery from the metal and the moon together. It marks the stage at which the matter is said to be purified but not yet fixed.
Sources The Secrets of AlchemyLawrence M. Principe with An Encyclopedia of Fairies: Hobgoblins, Brownies, Bogies, and Other Supernatural CreaturesKatharine M. Briggs