Sterling silver is a precious metal alloy composed primarily of silver, typically 92.5% by weight, with the remaining 7.5% usually consisting of copper. This alloy composition provides increased durability compared to pure silver, which is too soft for many practical applications, particularly in jewelry. The question of whether this material discolors the skin, specifically turning a finger green, is a common concern among consumers.
The phenomenon of skin discoloration from jewelry arises due to chemical reactions between the metal and substances on the skin, such as sweat, lotions, or soaps. The added metals in sterling silver, especially copper, are more prone to oxidation than silver itself. Copper oxidation produces a green compound (copper carbonate), which can transfer to the skin. The extent to which this occurs depends on individual body chemistry, environmental factors, and the specific composition of the alloy.