Pure gold is 24 karat.
Understanding Karat
Karat (kt or K) is a unit of measurement used to describe the fineness, or purity, of gold. The karat system divides the purity into 24 parts, where 24/24 signifies pure gold.
Here's a breakdown:
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24 Karat (24K): This is considered pure gold, meaning it contains 99.9% gold. In practice, it's nearly impossible to achieve 100% purity due to manufacturing limitations. It is also very soft and easily damaged, making it unsuitable for many jewelry applications.
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Lower Karatages: Lower karatages indicate that the gold is mixed with other metals, such as silver, copper, zinc, or nickel. These alloys enhance the gold's durability and alter its color.
- 18 Karat (18K): Contains 75% gold and 25% other metals.
- 14 Karat (14K): Contains approximately 58.3% gold and 41.7% other metals.
- 10 Karat (10K): Contains approximately 41.7% gold and 58.3% other metals. In the United States, 10K is the minimum standard for gold jewelry to be legally sold as gold.
Why Alloys are Used
Adding other metals to gold serves several purposes:
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Increased Durability: Pure gold is very soft and easily scratched or bent. Alloying it with other metals makes it stronger and more suitable for everyday wear.
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Color Variations: Different metals create different colors of gold. For example, adding copper creates rose gold, while adding silver and palladium creates white gold.
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Cost Reduction: Because pure gold is expensive, using alloys can reduce the cost of gold jewelry.
Gold Purity by Karat
| Karat | Gold Content (%) |
|---|---|
| 24K | 99.9% |
| 22K | 91.7% |
| 18K | 75% |
| 14K | 58.3% |
| 10K | 41.7% |
In summary, while 24 karat represents the purest form of gold available for consumer purchase, lower karat gold alloys are more practical for many applications due to their increased strength and versatility.
