- When buying gold jewelry, always look for the karat mark. All other things being equal, the higher the karat, the more expensive the piece.
- In the United States, 14-karat gold, or 583 parts pure gold, is the most common degree of fineness.
- Nothing less than 10 karats can legally be marked or sold as gold jewelry in the U.S. However, lower karatages, such as 8-karat gold and 9-karat gold, are popular in other countries.
- 18-karat gold is 18/24ths, or three-quarters pure gold, and jewelry of this fineness is marked 18k or 750, the European designation meaning 75% gold.
- Always look for the karat mark or "k" that appears on the back of the piece. By U.S. law, if a karat mark appears you should also see the manufacturer's trademark to assure you that the karat marking is accurate. The country of origin should also appear.
- In addition to the karat mark, every piece of gold jewelry should be stamped with a hallmark or trademark of its maker, and sometimes its country of origin.
- These designations assure you that you are buying genuine karat gold jewelry. Heavier pieces contain more gold.
- Gold Filled, also called Gold Overlay, refers to a layer of at least 10-karat gold that has been permanently bonded by heat and pressure to one or more surfaces of the support metal, then rolled or drawn to a prescribed thickness. The karat gold must be at least 1/10 of the total weight.
- Gold Plate means that a layer of plating of 10-karat gold or better has been bonded to a base metal. The karat gold content may be less than 1/20, but it must be properly identified by weight in terms of total metal content.
- Gold Leaf is just gold plating that's been pounded and applied by hand.
- Vermeil refers to gold plating that's at least 15 microns thick (one micron is a millionth of an inch).
