What is Gold Purity: The Differences Between Scale Levels

Understanding what gold purity means is an essential component of any evaluation of items that include gold. Karat levels are a measurement of what percentage of gold is inside a particular piece. The scale ranges from 0 to 24 karat, with 24K indicating that at least 99.9% of the item is composed of gold.

Further down the scale, 18K indicates that 75% of the item is composed of gold, while the remaining 25% is made of other metals. Those additional metals often include copper, silver or palladium. The additional metals help to decrease costs associated with gold items, such as jewelry, and can also help to boost the overall strength and durability of an item. 24K gold is considered too heavy and excessively soft for jewelry that’s expected to be worn every day.

While countries have their own standards for what percentage of gold something must have to be officially called “gold,” the minimum in the United States is 10K. This means that at least 41.67% of the alloy is made of pure gold.

Common Markings

When evaluating gold items, you can typically find these markings indicating the division of pure gold and other materials making up the full alloy:

• 24K / 999 / 999.9: Most often used in investment-grade bullion and coins
• 18K / 750: High-end jewelry that benefits from increased durability
• 14K / 583 or 585: High-quality jewelry at a more accessible price point
• 10K / 417: Higher durability, but lower luster than high karat counts

Gold Colors

The color of gold is influenced by the types of metals that are mixed with the pure gold. Those mixtures and end results include yellow gold, white gold and rose gold. For example, rose gold is mixed with a greater amount of copper than yellow gold, which includes a mixture of copper and silver. White gold, on the other hand, tends to include mixtures of palladium, nickel, or manganese.