The Different Types of Gold
Solid Gold Wire:
Solid Gold Wire is exactly that. It is solid gold and very expensive.
Gold-filled is more valuable than gold-plated. A piece of jewelry that is gold-filled is not solid gold, but it has a thick layer of real gold bonded to another metal. Since the piece is covered with real gold, it is virtually impossible to tell the difference between a solid gold piece of jewelry and a gold-filled piece of jewelry.
A gold plated piece has a thin layer of gold on the outside that is bonded to another metal. It will tarnish if not treated.
Gold Colored Wire:
Gold colored wire is copper wire that is plated with fine silver, colored gold, and then coated with a clear enamel. It is the easiest and least expensive way to get gold color in your work. While it is perfectly acceptable for fashion bracelets I do not recommend it for rings or other high wear items.