Sterling Silver or Silver 925 is the most valued in high jewelery and indicates that the metal alloy is made up of 92.5% pure silver. This is a standard that determines the highest degree of purity to guarantee the quality of jewelry manufactured with it. The term Prata de Lei was established in the 12th century by the King of Portugal, Dom Afonso II, when he decreed a law that punished anyone who manufactured silver pieces with lower alloys than this one, this international standard still applies today. In other words, the two names are synonymous and refer to the noblest alloy of the same valuable metal. In the same way as for gold, silver jewelery pieces are made in the form of an alloy (alloyed with other metals). Thus, the amount of silver present in a piece is indicated to the consumer through the contrast (925%, for example). In turn, silver bars correspond to silver 999% (thousandths), that is, silver not alloyed with other metals.