Sterling silver's origins
Sterling silver is thought to have originated in continental Europe, perhaps as early as the 12th century in Germany. It became extremely popular in the mid-19th century in the United States and Europe where its use for flatware and serving pieces proliferated, and separate items were used for virtually all courses at the well-set dinner table. More casual homes and lifestyles contributed to the decline of sterling silver's popularity during the 20th century.
Silver plate
Silver plated items exist because pure sterling silver items are expensive, as silver is scarce. Nickel or copper items are given a thin wash of silver, or the copper core is bonded to a layer of silver. This makes for a durable object, although the silver layer can wear thin over time.
How to tell the difference
Sterling silver is typically marked Sterling or .925, representing the fineness of the metal. A mark alone is not an absolute indicator of a piece being made of sterling silver.There is no quick and inexpensive way to test to see if an item is sterling or just plated. Some test kits can be used, although these are are destructive and will leave evidence of their use.
Tarnishing problems
Unfortunately, a problem inherent to the chemical makeup of silver is that it tarnishes with the passing of time. Once brilliant pieces of silver can become dark with charcoal, brown and grey tones that diminish the shine. Salt shakers especially are prone to corrosion because common table salt corrodes copper-silver alloys such as sterling silver.
Cleaning issues
Sterling silver takes well to cleaning and generally, tarnish can be removed with silver dip, which removes the top layer of surface to reveal the fresh, untarnished silver underneath. Silver polish can also be used to preserve the surfaces and restore shine. With silver plate, an issue arises when the silver layer gets too thin and there is very little silver to remove, making cleaning substantially more challenging.