What is the difference between gold fill, gold plate and vermeile?

gold plate is any metal, usually silver in jewelry or copper in electronics, coated with a very very thin layer of gold through an electrical or chemical process. several chemical processes of achieving plate are very hazardous. electrolysis, which involved placing the gold and the item to be plated both in an electrolytic solution and running current between them, is very common and very safe.

gold fill is a jewelry term, and it involves pressure-bonding a not so terribly thin layer of gold to another metal, again usually silver. visualize squeezing so hard that the two metals stick. there’s a lot more gold in gold fill than in gold plate.

vermeil is a very specific type of plate wherein the underlying metal is necessarily sterling silver, and the gold is a minimum of 1.5 micrometers thick and of a purity of at least 10 carats.