I'll bet you've seen things advertised as gold filled and gold plated & wondered what the difference is. In short, gold filled is better. Here's why:
In the US, the Federal Trade Commission dictates that the gold in gold filled items must make up 1/20 the total weight of the item.
Gold fill has a thick layer of gold on top of either sterling silver or another base metal like brass. Unlike plated jewelry, which has a relatively thin layer of gold over a base metal, gold filled pieces have a gold layer 5-10 times thicker than plating. Because of this, gold filled jewelry can last 10-30 years if cared for properly!
Gold plated jewelry is not awesome for those with sensitive or particularly acidic skin. For the folks with this sensitivity, within a few hours of wearing the gold can be completely gone and leave the skin with a not-so-lovely shade of dark green. On the other hand, gold filled jewelry is generally safe for sensitive skin. It's safe to wear your gold filled jewelry on the daily!
Gold filled items are the next best thing to solid gold jewelry. It's high quality and beautiful. Will gold filled last forever like solid gold? No, but with proper care you can wear your gold filled jewelry for many years!