18karat

18 karat gold, often abbreviated as 18K gold, is an alloy used primarily in jewelry and decorative items. It contains 75% gold by mass, with the remaining 25% made up of other metals such as copper, silver, nickel, zinc, or palladium. The karat system measures fineness relative to 24, with 24K being pure gold. An 18K designation therefore signifies a fineness of 0.75.

The choice of alloying metals influences color. Yellow 18K gold typically uses copper and silver to achieve its hue. White 18K gold is alloyed with nickel, palladium, or silver and is often plated with rhodium to enhance whiteness and durability. Rose or pink 18K gold has a higher copper content, giving a reddish tint. The exact metal mix can vary by manufacturer and region.

Properties and use: 18K gold offers a balance between gold content and durability, making it well suited for everyday wear in jewelry such as rings, bracelets, and watches. It is more resistant to scratching than higher-purity gold but softer than many other metals, so it can show wear over time. It is also more expensive than lower-karat gold due to its gold content.

Care and maintenance: Gold alloys do not tarnish, but white gold may lose its rhodium plating over time and require replating. Cleaning with mild soap and warm water, avoiding abrasive cleaners, and removing jewelry during activities that could cause scratches help preserve appearance.

Health considerations: Some white gold alloys contain nickel, which can cause allergic reactions in sensitive individuals. Ni-free white gold is available. 18K gold is commonly marked as 18K or 750 in many markets.