Why Does Gold Discolor Fingers?
Based on the article by Randy Welch, Research and Development You may think that faulty manufacturing or underkarating might be the problem when a ring “turns”, blackening or discoloring either your skin and clothing, or the jewelry itself. However, that is not the case. The most common reason is metallic abrasion, caused by makeup on the skin or clothing. Cosmetics often contain compounds harder than the jewelry itself, which wear or rub off very tiny particles. Very finely divided metal always appears black rather than metallic, so it looks like a jet-black dust. When this dust comes into contact with absorbent surfaces such as skin or clothing, it sticks, forming a black smudge. To prevent this, try switching cosmetics. If this is not possible, try to remove rings and other jewelry while applying them, and clean skin areas in contact with jewelry with soap and water. Another cause is the actual corrosion of the metals. Gold itself does not corrode, but its primary base-metal alloys of silver or copper will do so, forming very dark chemical compounds (under moist or wet conditions). When you perspire, fats and fatty acids are released and can cause corrosion of 14karat gold, especially when exposed to warmth and air. This problem can be worse in seacoast and semitropical areas, where chlorides combine with perspiration to form a corrosive element that discolors skin. Smog fumes gradually attack jewelry and are evident as a tarnish that rubs off on the skin. Try removing your jewelry often and using an absorbent power, free of abrasives, on skin that comes into contact with jewelry. Even the design of jewelry can be an influence. Wide shanks have more surface area to contact abrasives or corrosives. Concave surfaces inside a shank (a hollow underneath) form collection points that trap moisture and contaminants, also causing a type of dermatitis. Always remove all of your rings before using soaps, cleaning compounds or detergents, and clean your rings frequently.