When found on jewelry, "925 Italy" means that the item is at least 92.5 percent silver and that it is a product of Italy. "925 Italy" is only found on sterling silver, meaning silver that is actually a mixture of silver with other metals. "925 Italy" does not give any information as to which other metals the jewelry contains.
The vast majority of silver in the world is actually sterling silver, a material that is an alloy of silver combined with other metals. Silver is combined with other metals for a variety of reasons, but the most common of these is to improve its tensile strength. According to Merriam-Webster, sterling silver must be at least 92 percent pure. Most of the world's sterling silver contains about this percentage of the precious metal.
Pure silver, while very valuable, is simply too soft to make objects for everyday use. Rings, watches, bracelets and other worn silver jewelry items are at high risk for wear and tear, such as scratches, dings and other stresses. A damaged look would be undesirable in pure silver items. Mixing silver with small amounts of platinum, palladium, zinc or other strong metals preserves the attractive visual qualities of silver, while also providing a product that is far more resistant to damage than one made from pure silver.
"925 Italy" is one of thousands of types of imprints found on silver. Modern silversmiths continue the traditions of their ancestors by stamping their products with both purely informational marks, such as "925 Italy," and distinct maker's marks and artistic signatures.