Understanding Different Types of Gold
Gold has been valued across cultures for thousands of years. While most people immediately picture the classic yellow metal, gold actually comes in a variety of hues, each defined by its purity and alloy composition. Understanding these differences, not just the color, but also durability and karat levels, helps you better assess gold’s true worth. This article explores the colors, alloys, and properties of gold, and explains how these factors influence its overall value.
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What determines the color of gold?
Gold purity is measured in karats, with 24 karats representing pure gold, free of any mixed metals. In this form, gold displays a rich, saturated yellow hue and serves as the benchmark for measuring all other levels of purity.
When other metals, or alloys, are introduced, the color and purity of gold change. Mixing gold with these alloys lowers its karat value, for example, 18k or 14k gold, resulting in a paler, less vibrant yellow tone. The specific metals used also influence the final shade, creating a variety of beautiful colors beyond classic yellow.
Gold purity affects more than just color; it also determines softness and durability. Pure 24k gold is quite soft, making it susceptible to scratches, dings, and bending, which limits its use in everyday jewelry. Instead, it’s often reserved for investment forms like bullion, as well as applications in electronics, aerospace, dentistry, and medical devices. For jewelry, gold is alloyed to improve strength, producing lower-karat pieces that can better withstand daily wear.
Yellow Gold
Yellow gold is known for its classic, warm golden hue. To achieve this color, pure gold is mixed with alloys such as silver, copper, or zinc. The type and amount of alloy used influence the tone, warmth, and durability of the metal. A higher ratio of alloy increases the metal’s strength while slightly lightening its color.
With silver as part of the alloy, yellow gold is generally hypoallergenic and unlikely to cause rashes. It is also mostly tarnish-resistant, making it ideal for everyday wear.
- 22 karat yellow gold: Approximately 91.7% gold, with the remainder made up of alloy metals.
- 18 karat yellow gold: Contains 75% gold and 25% other metals, typically copper or silver.
- 14 karat yellow gold: About 58% gold, with the rest composed of alloy metals for added strength and durability.
White Gold
White gold has a silvery-white appearance, similar to silver or platinum. It is made from alloys such as palladium, platinum, and sometimes nickel or zinc. Thanks to the platinum and palladium content, white gold is known for its durability and scratch resistance. White gold is typically available in 10k, 14k, and 18k.
Since white gold is not naturally white but more of a pale yellow, it is often plated with a thin layer of rhodium to achieve a bright white finish. This plating can wear off over time and may need to be reapplied periodically to maintain its appearance.
Rose Gold
Rose gold is a color that has grown increasingly popular in modern jewelry. Its distinctive pink or blush hue is not natural; rather, it is achieved by mixing gold with a higher percentage of copper; sometimes silver is also added. Rose gold has a romantic, elegant appeal, which has contributed to its growing popularity.
Thanks to the copper content, this metal is durable and well-suited for everyday wear. Additionally, because copper and silver are relatively low-cost metals, rose gold is often a more affordable option compared to other types of gold. Rose gold is typically available in 10k, 14k, and 18k.
Other Types of Gold
As you can see, the addition of different alloys allows gold to take on a wide range of colors, more than most people realize. This versatility makes gold a unique choice for jewelry, available in various hues and karat types with differing purity levels.
- Green Gold – Achieved by mixing gold with silver and sometimes copper. The green tint comes primarily from the silver content. It can also be made using cadmium, though this alloy is toxic to skin. The proportion of alloys determines the shade of green, which can range from light to deep tones.
- Black Gold – Created using specific alloys like cobalt or through surface treatments. These treatments can include electroplating with black rhodium, oxidation, or laser treatment, giving the metal a dark, striking finish.
- Blue Gold – Produced by alloying gold with metals such as indium or gallium, which are melted together to form a new compound. Alternatively, it can be made by heat-treating gold alloyed with iron and nickel, creating an oxidized layer that gives it a blue hue. However, both methods result in a brittle material, making it more difficult to work with than other gold alloys.
- Purple Gold – Formed by alloying gold with aluminum, most commonly at a ratio of 75% gold and 25% aluminum, qualifying it as 18 karat. This combination forms an intermetallic compound, meaning it is not just colored gold but a new material with distinct physical properties.
Bringing It All Together: Purity, Alloys, and Worth
Gold is more than just the yellow metal most people picture. Depending on its purity and the alloys it’s mixed with, gold can take on a wide spectrum of colors, strengths, and applications. Each variation, from the timeless warmth of yellow gold to the romantic glow of rose gold or the sleek appeal of white gold, offers its own balance of beauty and durability.
These differences in composition don’t just influence color and wearability; they also impact the true value of the metal. Because alloys alter purity, they can shift the worth of gold when refined. The higher the karat, the greater the gold content and intrinsic value; the lower the karat, the more alloy present, resulting in less pure gold recovered during refining.
Understanding these distinctions is key when evaluating or refining precious metals. Recognizing how alloy content and purity affect gold’s overall value ensures transparency and accuracy, especially when reclaiming or recycling materials through the refining process. Wondering how much your gold is worth? Contact Core Scientific for a free consultation.
