You are looking at a gold chain, trying to figure out its karats, but you are not sure how to do that? Let’s see how you can find out the karats of a gold chain, and what this number actually means.
What Does the Karat of a Gold Chain Mean?
Karat is a unit used to measure the purity of gold alloys. If a gold chain is 14 karats, for example, this means that of every 24 parts of the alloy that makes up the piece, 14 parts are pure gold and 10 parts are other metals.
To figure out the percentage equivalent of a karat number, divide the karats by 24 and multiply the result by 100.
In our example with the 14-karat chain, dividing 14 by 24 yields 0.583, which is equal to 58.3% pure gold content.
Reading Karat Marks on Gold Chains
One way to find out how many karats there are in a gold chain is to look for hallmarks on it.
These stamps should show the purity of the gold alloy in karats or parts per thousand.
Interpreting karat marks is straightforward: 10K stands for 10 karats, 18K means 18 karats, and so on.
If the gold purity of a chain is expressed in parts per thousand, however, you will see a 3-digit number instead of karats.
For example, a mark that reads “583” means that the piece contains gold in the proportion of 583 parts per thousand, which is equal to 58.3%, or 14 karats.
In general, to convert a parts-per-thousand number to karats, simply divide the number by 1000, and then multiply it by 24.
For example, if you see a hallmark that reads “750”, you can calculate that 750 divided by 1000 times 24 equals 18, and therefore, the item is 18 karats pure.
Some other common parts-per-thousand numbers are 917 for 22 karats, 833 for 20 karats, and 417 for 10 karats.
Testing Gold Chains for Karats at Home
If there are no marks on the chain, the best way to find out its karats is to test it for purity. One way to do so is at home. You will need to buy a gold testing kit. (Here you can find a selection of different gold testing kits.)
The most common type of gold testing kit includes small bottles with nitric acid and a testing stone. This is how testing usually works:
- To test a gold chain for karats, first you need to scratch the testing stone with it so as to leave a gold mark.
- Then, pick the acid bottle labeled “14K”, and drop some acid on the mark.
- If the gold mark doesn’t change in color, then the chain is more than 14 karats. Continue testing with the higher-karat acid bottles, and repeat until the gold mark starts to change or dissolve – this will indicate that its karat is less than what is written on the label of the last acid bottle you used.
- If the mark’s color changes slightly after being treated with the 14K acid, then the jewelry is 14 karats or slightly below this level.
- If after testing with the 14K acid the gold mark starts to become faint and dissolves, this means that the chain is less than 14 karats, most likely 10K, but you should check using the 10K bottle.
Professional Karat Testing for Gold Chains
If you don’t want to test the gold chain yourself, take it to a jeweler to have it tested by a professional.
The method jewelers use to determine the karat of gold is similar to the testing kit procedure described above. The process usually involves taking a tiny sample from the chain and treating it with nitric acid to see how the gold reacts.
Most jewelry stores provide such testing services for a fee.