Gold, often associated with lasting brilliance, frequently prompts questions about its susceptibility to tarnish. Whether gold tarnishes depends on its purity and how it is used. Understanding gold’s characteristics and its applications in jewelry can clarify this common inquiry.
The Intrinsic Properties of Pure Gold
Pure gold, or 24-karat gold, is a noble metal highly resistant to environmental reactions. It does not readily combine with oxygen or other elements in the air, preventing oxidation and tarnishing.
This resistance means 24-karat gold will not corrode or tarnish under normal conditions, maintaining its shine indefinitely. However, pure gold is exceptionally soft. Its softness makes it impractical for durable jewelry, leading to the creation of gold alloys for most pieces.
Understanding Tarnish in Gold Jewelry
While pure gold resists tarnish, most gold jewelry is an alloy. Pure gold is mixed with other metals like copper, silver, nickel, zinc, and palladium to enhance strength, durability, or alter color. These added metals are susceptible to tarnishing.
Tarnishing occurs when these reactive metals chemically react, often with sulfur compounds or chlorine, forming a dark surface layer. Sulfur is present in the air, certain foods, and human perspiration. When copper or silver reacts with sulfur, it forms sulfides, appearing as a dull film. Chlorine, found in swimming pools and some cleaning products, can also cause corrosion and discoloration.
Other environmental factors contributing to tarnish include humidity, moisture, skin oils, and residues from cosmetics, perfumes, and lotions. Human sweat, especially if sulfur-rich, can accelerate this process. The karat system indicates the proportion of pure gold in an alloy; for example, 14-karat gold is 58.3% pure gold, while 10-karat gold is 41.6%. Lower karat gold jewelry, having a higher percentage of reactive metals, is more prone to tarnishing.
Preserving Your Gold’s Shine
Maintaining gold jewelry’s luster requires proactive care and cleaning. To prevent tarnish, remove jewelry before activities exposing it to harsh chemicals, such as swimming in chlorinated pools, cleaning with household products, or showering. These chemicals can react with alloyed metals, causing discoloration. Apply cosmetics, perfumes, and lotions before wearing jewelry, allowing them to dry completely.
Proper storage also prevents tarnish. Store gold jewelry in a cool, dry place, away from direct sunlight and humidity. Use individual compartments, soft fabric pouches, or velvet-lined containers to prevent scratching and minimize air exposure. Anti-tarnish strips or silica gel packets can absorb excess moisture and pollutants, further protecting jewelry.
For cleaning, a simple solution of mild dish soap and warm water is generally effective for most gold jewelry. Soak jewelry for a few minutes, then gently scrub with a soft-bristled toothbrush to dislodge dirt from crevices. After cleaning, it is important to rinse thoroughly with clean water and dry completely with a soft, lint-free cloth to prevent water spots and further tarnish. For more stubborn tarnish, a baking soda and water paste can be applied gently. If tarnish persists, professional cleaning may be necessary.