If you have ever looked closely at a piece of gold jewellery, you may have noticed a small stamp — 9K, 14K, or 18K — pressed into the metal. These markings indicate the purity of the gold, and they play a significant role in determining what your piece is actually worth. Understanding karats can help you make better decisions whether you are buying, selling, or simply curious about what is sitting in your jewellery box.
What Is a Karat?
A karat is a unit of measurement for gold purity. Pure gold is 24 karats, meaning it contains 99.9 percent gold. However, pure gold is extremely soft and not practical for everyday jewellery. That is why gold is alloyed — mixed with other metals like copper, silver, or zinc — to make it harder and more durable. An 18K piece contains 75 percent gold, 14K contains 58.3 percent, and 9K contains 37.5 percent. The remaining percentage is made up of those strengthening alloy metals.
How Purity Affects Value
The higher the karat rating, the more gold content the piece contains, and the more it is worth by weight. When you sell gold, the buyer will first determine the karat rating and then weigh the item on a certified scale. The value is calculated based on the weight of pure gold in the piece, multiplied by the current market price per gram. For example, 10 grams of 18K gold contains 7.5 grams of pure gold — so that is the figure used in the calculation, not the full 10 grams.
Common Karat Ratings in Australia
In Australia, the most common karat ratings for jewellery are 9K, 14K, and 18K. Older pieces may also be marked in parts per thousand — 375 for 9K, 585 for 14K, or 750 for 18K. Investment-grade gold bars and coins are typically 24K or 99.99 percent pure. If your jewellery has no visible markings, a professional gold buyer can test it using acid testing or electronic XRF analysis to determine the exact purity without damaging the piece.
Why It Matters When Selling
Knowing the karat of your gold helps you understand the offer you receive. If you bring in a mix of 9K and 18K pieces, the 18K items will be worth roughly twice as much per gram because they contain twice the gold content. A transparent buyer will separate your items by purity, weigh each group individually, and show you exactly how the total is calculated. At Imperial Gold Buyers, we walk every customer through this process so there are never any surprises.
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Imperial Gold Buyers
