What does 128 stamped on silver mean?

The number 128 stamped on silver typically indicates the purity of the metal, specifically that it is 92.5% silver and 7.5% other metals, most commonly copper. This is a hallmark for sterling silver, which is the standard for high-quality silver items. The "128" does not represent a standard marking but could be a manufacturer's specific code or a design number, so it's important to consider the context in which it appears. Always verify with a reputable jeweler for accurate identification.