Amulet of the Necrotic Rust

A superbly crafted amulet of a red stone with veins of an iridescent copper color running through it, set in and on a chain of a bluish silver metal held within an ornate, wax-sealed, golden box.  This amulet generates a field with a 30-foot radius that causes all iron items with a portion of their make-up exposed to air to develop lines of rust to form on them.  The items will dissolve into rust in 2d12 hours, leaving only those non-iron portions intact.