and other common metals, mainly because niobium jewelry is more expensive and more difficult to produce. Bronze Bronze is often used in larger piercings in the form of earweights and ethnic jewelry from Indonesia and other places of the world. Bronze is an alloy of different metals but the most common blend (in piercing jewelry) is 90% copper and 10% tin. When buying bronze jewelry, make sure to buy it from a serious manufacturer as some bronzes can contain arsenic which can "bleed" into your body. Bronze can also discolor the skin with a greenish color which can be removed but if it gets into open wounds it can permanently discolor the tissue. Silver Jewelry made out of silver, a noble metal, has been common for centuries in all forms of jewelry. It has a certain luster and can also be treated to make certain areas black which gives a nice contrast. Gold Gold is a noble metal with a long tradition for use in jewelry. When using gold for piercings, a lower purity than 14 or 18 carat (58 to 75%) is not recommended. Gold is about as soft as lead and is easily scratched. These scratches can irritate the body, especially in new piercings. Tongue jewelry made from gold is not recommended as chewing on the beads is common. To avoid the irritation of damaged jewelry from such scratches and flaws, gold colored titanium jewelry is a safer substitute. Piercing jewelry is often made of a gold alloy, the most common being 18k, with 24k being entirely pure and much softer. 18k gold usually contains 75% gold and the remaining 25% copper, silver and traces of other metals. In lower quality gold, zinc, nickel and other irritants can also be found. As said, gold jewelry should only be used in healing piercings if it is nickel free or palladium based. Allergy to gold is uncommon but it does exist, and then mostly from white gold. In some extreme cases, the copper in the jewelry can tarnish and cause greenish discoloring of the tissue. Gold can become discolored from autoclaving. It could be several things, reaction to the chemical indicators, residues left from polishing or cleaning products, or corrosion of elements in the gold itself. Experienced body piercing studios clean the jewelry with a jewelry steamer, and then an ultrasonic process with warm alkaline detergent, followed by a distilled