There are different types of plating that can be applied to silver jewelry. In most cases, the plating is done to give the jewelry better protection against scratches, to give it a different look/color, or to protect it from tarnishing.
Gold Layer - a fine sheet of gold is placed on top of the item, cut into shape and then soldered in place. The item is then polished smooth. Gold layer is more substantial than plating.
Gold Plating - a fine layer of gold which has been electroplated onto the item. This layer can be quite fine or quite deep
Rhodium finish -a fine layer of rhodium is electroplated onto the item. Rhodium is very bright and shiny like highly polished silver.
Rhodium belongs to the Platinum group of metals. All of them present outstanding chemical inertness (will not react or change easily) thus, rhodium will not tarnish whereas silver will. They are very expensive, so only a very thin plate is applied to reduce the amount of metal in the jewel. If not subject to excessive friction and wear, they will retain their look indefinitely.
Rhodium is the rarest and most expensive of all metals used in jewelry.
Palladium/Ruthenium finish - a layer of palladium or ruthenium is laid onto the item to form a pattern.
Ruthenium plating on sterling silver jewelry gives a dark grey black finishing that answers the call for a different color. In addition, ruthenium can effectively prevent scratches and abrasion on the surface, making sterling silver jewelry more durable. With ruthenium plating, surface oxidation and discoloring can be avoided to a large extent.
Cleaning your jewelry - It is very important to clean these types of finishes carefully - vigorous rubbing with a silver cloth will eventually wear the silver/gold/rhodium/palladium or ruthenium away.
For plated items with a textured finish, clean using either a silver dip type product and wash thoroughly. Dry using a soft towel and leave it to dry in a warm atmosphere.