As a subject matter expert in precious metals and jewelry, I can provide you with accurate information regarding gold purity and its various markings.

Gold is often marked with a purity level, which indicates the amount of gold in the alloy. The purity of gold is usually measured in karats (K) or parts per thousand (ppt).

In the United States, gold is commonly marked in karats, while in Europe and other parts of the world, it is often marked in parts per thousand. The term "9ct" stands for "9 carats," which means that the gold is 37.5% pure gold. This is because there are 24 parts in a whole karat, so 9 out of 24 parts is 37.5%.

To convert carats to parts per thousand, you can use the following formula:

\[ \text{Parts per thousand} = \text{Carats} \times \frac{1000}{24} \]

Applying this formula to 9 carats:

\[ \text{Parts per thousand} = 9 \times \frac{1000}{24} = 375 \]

So, 9ct gold is indeed 375 parts per thousand, which means it is 37.5% pure gold.

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The number refers to the fineness of gold in parts per 1000. All these marks are acceptable as it depends on where it was made. There are many carats used in jewellery. ... 9K, 9ct or 375 (parts per 1000) or is 37.5% gold (mainly British Commonwealth countries.read more >>