Carats and karats. The higher the karat rating, the higher the proportion of gold in the piece of jewelry. Gold-plated describes jewelry with a layer of at least 10K gold bonded to a base metal. Gold plating eventually wears away, depending on how often the item is worn and how thick the plating is. Gemstones Gemstones can be naturally mined, laboratory-created or imitation.
Stones created in a lab look identical to stones mined from the earth.
But because they look just like stones mined from the earth, they must be identified as lab-created. Imitation stones resemble naturally mined stones but are not identical and are usually made of glass or plastic. Imitation stones must be identified as imitation. If you are purchasing a naturally mined stone, ask if it has been treated. Treatments also may affect the stone's value.