White gold, prized for its lustrous, silvery appearance, is not a naturally occurring metal. It is a carefully engineered alloy created by blending pure yellow gold with other white-hued metals. This manufacturing process is necessary because pure gold is far too soft for practical use in jewelry. The final color and durability depend on the specific ratio and type of metals used in the blending process.
White Gold is a Manufactured Alloy
An alloy is a mixture of metals combined to enhance the properties of the primary metal. Since pure gold is naturally yellow and highly malleable, it must be mixed with whiter metals to counteract the yellow hue and increase strength. The purity of the gold alloy is measured using the karat system: 24 karats represents 100% pure gold. Therefore, 18-karat white gold contains 75% gold, while 14-karat white gold consists of 58.3% gold. White gold typically follows one of two main recipes using different whitening agents.
The first, and historically more common, uses nickel as the primary alloying metal. Nickel alloys are particularly hard and durable, making them a strong and less expensive choice for jewelry.
The alternative, and increasingly popular, formula uses palladium to whiten the gold. Palladium white gold is naturally hypoallergenic, avoiding the skin irritation sometimes caused by nickel. This alloy is generally softer and more pliable than the nickel version, making it ideal for setting intricate gemstones. However, it is typically more expensive due to the higher cost of palladium. Regardless of the alloying agent used, the resulting metal often possesses a slightly grayish or pale yellow tone, which is addressed in the final manufacturing step.
Geographic Sources of Raw Gold
The pure yellow gold used to create white gold is sourced from geological deposits across the globe. Gold mining is concentrated in specific regions where geological processes have created high concentrations of the metal. The world leaders in production volume are:
- China
- Australia
- Russia
- The United States
- Canada
- Mexico
Gold deposits are categorized into two main types based on their formation environment. Primary or lode deposits consist of gold embedded in quartz veins within igneous and metamorphic rock formations. These deposits are formed deep within the Earth by hot, mineral-rich hydrothermal fluids that solidify into rock. Secondary deposits, also known as placer deposits, result from the erosion of primary deposits over millions of years. Water carries the heavy gold fragments to collect in stream beds, river bottoms, and alluvial fans.
Origin of Essential Alloying Metals
The metals used to transform yellow gold into a white alloy are sourced from specialized mining operations worldwide. Palladium, the preferred hypoallergenic whitener, is a platinum group metal. Its global supply is highly concentrated, with Russia and South Africa dominating the production market. Palladium is often mined as a byproduct of platinum and nickel extraction. Other significant producers include Canada and the United States, with output often linked to their own platinum and nickel mining activities.
Nickel, used in durable and less expensive white gold alloys, is produced in high volumes by countries like Indonesia and the Philippines. These nations extract nickel from large laterite deposits found near the Earth’s surface. Russia is also a major nickel producer.
Minor metals like silver and copper are often included in white gold formulations to adjust the color, malleability, or melting point. Silver is widely sourced from countries such as Mexico, Peru, and China, often as a co-product in the mining of other base metals. Copper is also a globally accessible metal, with Chile and Peru being two of the largest producers.
The Final Step Rhodium Plating and Karat Definition
The final step in producing the brilliant white gold seen in jewelry stores is rhodium plating. White gold alloys naturally have a slightly off-white appearance, described as gray or pale yellow. To achieve a mirror-like, pure white finish, the item is electroplated with a very thin layer of rhodium.
Rhodium is a precious metal in the platinum group that is exceptionally bright, hard, and resistant to corrosion. The electroplating process involves submerging the jewelry in a chemical bath containing rhodium solution and running an electric current through it, bonding the rhodium layer to the surface of the gold alloy. While this layer provides the desired aesthetic, it is not permanent and may wear down over time, requiring re-plating.
The finished product must also adhere to legal standards regarding the disclosure of its gold content. In the United States, regulations require that the gold content be accurately stamped on the item, such as “14K” or “18K.” If the gold has a temporary surface coating like rhodium, the seller should disclose the presence of the plating to the consumer.