The darkening of skin sometimes observed after wearing gold jewelry is often attributed to a chemical reaction. This phenomenon, while giving the appearance of gold “turning” the skin black, is generally not caused by the gold itself. Instead, it is frequently the result of other metals alloyed with the gold reacting with substances on the skin.
Understanding the composition of gold jewelry is crucial to comprehending this discoloration. Pure gold is very soft and malleable, making it unsuitable for most jewelry applications. Therefore, gold is typically alloyed with other metals like silver, copper, nickel, or zinc to increase its durability and alter its color. These other metals are susceptible to oxidation and reaction with acids, salts, and other compounds found in perspiration, cosmetics, and even some medications absorbed through the skin. The resulting chemical reactions can produce compounds like silver sulfide or copper oxide, which appear as a dark or black residue on the skin.
