In creating jewelry, gemstones, coins, or other precious items are often used, and they are typically set into precious metals. Alloys of nearly every metal known have been encountered in jewelry -- bronze, for example, was common in Roman times. Modern fine jewelry usually includes gold, white gold, platinum, palladium, titanium or silver. Most American and European gold jewelry is made of an alloy of gold, the purity of which is stated in karats, indicated by a number followed by the letter K. American gold jewelry must be of at least 10K purity (41.7% pure gold), (though in England the number is 9K (37.5% pure gold) and is typically found up to 18K (75% pure gold). Higher purity levels are less common with alloys at 22 K (91.6% pure gold), and 24 K (99.9% pure gold) being considered too soft for jewelry use in America and Europe. These high purity alloys, however, are widely used across Asia, the Middle East, and Africa. Platinum alloys range from 900 (90% pure) to 950 (95.0% pure). The silver used in jewelry is usually sterling silver, or 92.5% fine silver. In costume jewelry, stainless steel findings are sometimes used.

Other commonly used materials include glass, such as fused-glass or enamel; wood, often carved or turned; shells and other natural animal substances such as bone and ivory; natural clay; polymer clay; and even plastics. Hemp and other twines have been used as well to create jewelry that has more of a natural feel. However, any inclusion of lead or lead solder will cause an English Assay office (the building which gives English jewelry its stamp of approval, the Hallmark) to destroy the piece.