Silver trademarks are useful for identifying the maker of the silver product, which can determine the quality of the silver itself. Knowing the quality of the metal allows for an accurate appraisal.
Silver trademarks are commonly referred to as hallmarks. The most basic purpose of a hallmark is to record the purity of the silver. The ratio of silver to other metals in a given piece is known as fineness, and is defined as the number of silver particles per thousand. Most countries have standards for the fineness of silver products. A list of these standards can be found on the Online Encyclopedia of Silver Marks, Hallmarks, & Maker's Marks.
Hallmarks often appear as three-or-four digit numbers stamped into the metal itself. Reading the hallmark gives an indication of both the purity of the silver object and its country of origin. A hallmark may also give a clue as to the date of manufacture of the object. Knowing when and where an item was created can be useful in determining the value of a piece. For example, a piece of silver jewelry with a boar's head hallmark would have been manufactured in France and should have a fineness of at least 800 parts per thousand.