The related term 'Nepalese silver', however, seems to have held on to the higher silver content and association with quality metalsmithing. Currently, jewelry, beads and castings described as 'Tibetan Silver' tend to be a base iron 'cheese metal' casting, overlaid with this pewter and silver plating.Dependent on source, these can be either thick and robust, or attractive but easily broken due to a loose, fragile inner casting.urrently, jewelry, beads and castings described as 'Tibetan Silver' tend to be a base iron 'cheese metal' casting, overlaid with this pewter and silver plating. Dependent on source, these can be either thick and robust, or attractive but easily broken due to a loose, fragile inner casting.