Sterling Silver
Sterling silver is the grade of silver used for most silver jewelry, tableware and ornamental objects. It's a mixture of 92.5-percent silver and 7.5 percent other metals, usually copper. The copper strengthens the silver and makes it more suitable for working into functional items. Pure silver, or fine silver, is too soft by itself to use for durable silver pieces.
Silverplate
Silverplate items appear very similar to sterling items. This is because silver plate is a layer of silver fused onto the surface of another solid metal, usually copper. Techniques used to create silver plate include the heat method, where pressure and heat are applied to the silver layer to fix them to the copper. This is the technique used to manufacture one of the most famous forms of silver plate: Sheffield Old Plate. More recent techniques include electroplating.
Appearance
Superficially, silver and silverplate looks very similar. However, several blemishes may appear on silverplate items. For example, green, red or yellow regions can be a sign that the foundation metal beneath the silverplate is showing through the thin plate layer.
Value
Sterling silver and other high-grade silver nearly always sells for higher prices in antique shops and auctions than silverplate. However, some silverplate items are sought after and can reach high sales prices, such as Old Sheffield Plate. This is a type of silverplate dating from the 1740s to the 1840s.
Hallmarks
Most antique and quality modern silver is stamped with a hallmark. Hallmarks can identify maker, location, date and type. Marks are also found on many forms of sterling silver. The stamp "925" or the word "sterling" means that the item is silver, not silverplate. Hallmark guides offer a list of other international hallmarks that show sterling silver authenticity. The stamped letters "EPNS" stand for electroplated nickel silver, a form of silver plate. "EPBM" stands for electroplated base metal. This too identifies a type of silverplate.