Sterling silver, commonly identified with the “s925” hallmark, is an alloy composed of 92.5% silver and 7.5% other metals, typically copper. This combination enhances the durability of the pure silver, which is inherently soft. However, the presence of the additional metals introduces susceptibility to a chemical reaction with environmental elements, specifically sulfur-containing compounds.
The formation of a dark, often black, layer on the surface of sterling silver is a frequently encountered phenomenon. This discoloration, known as tarnish, is a result of the silver reacting with hydrogen sulfide and other air pollutants. While tarnish is a surface-level alteration, its presence can detract from the aesthetic appeal of the item. The rate at which this surface alteration occurs is influenced by factors such as humidity, exposure to certain chemicals (e.g., perfumes, chlorine), and individual skin acidity.
