Rose gold is a popular metal for fine jewelry, prized for its distinctive, warm pinkish hue that offers a romantic alternative to traditional yellow or white gold. As with any metal, people often question its durability and how it will hold up over time, especially when exposed to moisture and the elements. The concern over whether this unique alloy can “rust” is common, and understanding the metal’s composition is the first step in addressing this question. Rose gold does not rust, but it can undergo a surface change that is often mistaken for rust.
The Composition of Rose Gold
Rose gold is not a pure element but is instead an alloy, which is a blend of pure gold and other metals. Pure 24-karat gold is too soft for everyday jewelry, requiring it to be mixed with other metals for strength and color variation. The signature pink tone of rose gold is primarily achieved by mixing pure gold with copper.
The specific ratio of gold to copper, and often a small amount of silver or zinc, determines the final color and the karat rating of the piece. For example, 18-karat rose gold is composed of 75% pure gold and about 25% copper. A lower karat, such as 14-karat rose gold, contains a greater percentage of copper, leading to a deeper red hue and increased durability. This copper component is responsible for any eventual discoloration seen on the metal’s surface.
Rust Versus Tarnish
Rose gold does not rust because gold and copper do not contain iron, which is the element required for rust to form. Rust is the specific term for iron oxide, a reddish-brown, flaky compound that occurs when iron reacts with oxygen and moisture. This process progressively weakens and degrades iron-containing metals.
The discoloration seen on rose gold is known as tarnish, a fundamentally different chemical reaction. Tarnish is the oxidation of the copper component in the alloy, which forms compounds like copper sulfide or copper oxide. Unlike rust, which flakes away and exposes new metal, tarnish forms a relatively thin, stable layer on the surface. This surface layer typically appears as a darkening or dulling of the metal.
Tarnish occurs when the copper content interacts with sulfur compounds in the air, moisture, and oils from the skin. While pure gold is resistant to this process, the copper in the rose gold alloy makes the metal susceptible to this surface change over time. The resulting layer, often called a patina on pure copper, can actually act as a protective barrier for the underlying metal.
Practical Care and Maintenance
Simple care practices can significantly slow the tarnishing process. It is advisable to remove rose gold jewelry before exposing it to harsh chemicals, such as household cleaners, chlorine from pools, or bleach. These substances can accelerate the oxidation of the copper alloy, leading to faster discoloration.
Cleaning the metal regularly with mild soap and warm water is an effective way to remove oils and residue. A soft-bristled toothbrush can gently scrub away debris. The piece should then be rinsed thoroughly and immediately dried with a soft, lint-free cloth.
Proper storage is also important. Keeping rose gold pieces in a cool, dry place, ideally in separate soft pouches or compartments, will limit exposure to air and prevent scratching.