This padlock has a reasonably high silver content in the metal.
Padlocks with this type of mechanism in the Tanavoli collection date from the sixteenth and seventeenth centuries. This padlock, however, appears to bring the date back to the thirteenth century, of which period this style of engraved decoration is typical.
Tanavoli, P, and Wertime, J.T.: Locks from Iran, the Parviz Tanavoli Collection, Smithsonian Institution, Washington D.C., 1976