The stamp inside a ring, bracelet or other piece of jewelry is used by the manufacturer to indicate the manufacturer's or designer's name, the metal purity and type. Called hallmarks or assay marks, there are a very large number but in terms of valuation, the most important deal with metal type and purity.Continue Reading
Silver purity is given in a numerical code, which refers to its purity across a thousand parts.
Gold may be indicated as a karat weight, or K, or also as a numerical code referring to its purity over a thousand parts, based on pure gold being 24 karats.
Other metals use varying formats to indicate type. Base metals hallmarks only indicate the type of metal and not its purity.