Vintage 18k yellow gold diamond cluster ring w/diamond set in white gold cluster

The mark "18K GP" on a ring indicates that it is 18-karat gold plated, not solid gold. This means a very thin layer of 18K gold (which is 75% pure gold) has been applied over a base metal, such as brass or copper, typically through an electroplating process. Key Details Composition: The bulk of the ring is made of an inexpensive base metal. Gold Layer: The outer layer is real 18K gold, but it is microscopically thin, usually less than a micron in thickness. Durability: The thin plating can wear off over time, especially with frequent use, revealing the base metal underneath, which may tarnish or cause skin irritation. A ring stamped "18K GP" (gold plated) is a piece of costume jewelry and typically costs anywhere from $50 to $150 when new. The resale or pawn value for such items is generally negligible, often just a few dollars, if anything at all. Factors Affecting Price Material Value: The ring's value does not come from precious metal content, as the gold layer is microscopically thin and cannot be profitably refined. The price reflects only the manufacturing and design costs. Stones: The stones in gold-plated rings are usually not real diamonds or precious gemstones; they are most often simulated stones like cubic zirconia (CZ) or rhinestones, which hold very little value. Condition: Because the plating is thin, wear and tear significantly reduce any perceived value the ring might have. New condition items would command the higher end of the price range.