How to Verify the Purity of 24 Carat Gold?

For centuries, gold has been a prized possession because of its beauty and radiance. Being an extremely versatile metal, it is best suited for making jewellery. Besides being malleable and ductile, this precious metal is free from rusting and corrosion. Karat is a term used to measure the purity of gold. This means that the higher the karat, the purer the gold. There are various karats of gold available in the market, ranging from the purest 24K to 10K. As pure gold, or 24 karat gold, is too malleable, it is not fit to be used in jewellery. So the gold is alloyed with various metals, including zinc, nickel, copper and silver to increase its durability and strength.

Is Gold Jewelry Likely to Be Made of Pure Gold?

Because of its softness, pure gold is rarely used to make jewelry. Items made of 24K gold bend very easily, and this is why pure gold is not a good choice for pieces that will be worn as adornment. Not to mention that any settings made of pure gold would wear out pretty quickly, making it easy for any stones in them to fall off.

The gold that is used to make jewelry is actually a gold alloy – a mixture of pure gold and other metals, which are added in to make the alloy harder.

Testing Gold for Purity

Usually, gold jewelry comes with markings stamped on it that indicate what its karat is. If there are no marks or if you just want to check whether the gold is as pure as it is claimed to be, you can test it. There are different methods, but the most reliable one is acid testing.

Acid Testing

You can have your gold tested for purity at most jewelry stores. The jeweler will scratch the gold on a testing slab to take a sample of it and will then pour some acid (usually nitric acid) on the sample to see how it reacts.

Depending on the chemical reaction observed, the karat of the gold can be determined. You can also purchase a testing kit with nitric acid and test the gold yourself. Here is how such a test is usually performed:

• Scratch the gold on the testing stone provided so that the piece leaves a mark.
• The kit will contain bottles with acid of varying concentration, and each will have a karat number written on its label. Drop a little acid from the bottle with the lowest karat number on the scratch mark and observe the reaction.
• If the gold is a higher karat than the label on the bottle, then you won’t see any change in the mark’s color. In such a case, repeat Step 2 by using the bottle labeled with the next lowest karat number.
• If the gold is the same karat as the number on the label, or within +/- 1 karat of it, the color of the mark will change, but only slightly.
• If the gold’s karat is more than 1 karat lower than the number on the bottle, then the portion of the mark where acid has been applied will be dissolved and will disappear.

Don’t forget to read the instructions enclosed with the testing kit because the exact procedure might differ from the general method described above.

Other Methods to Test for Gold Purity

There are other methods to test the purity of gold that have become popular. However, despite their popularity, they are actually close to useless.

• Biting a gold piece is said to be a good indicator of whether it is real, as gold is a very soft metal. However, there are many other metals that are also soft and can be covered with gold plating to make them look like gold, so biting them won’t show you conclusively whether you’re dealing with gold.

• It is also said if a gold piece is not attracted to a magnet, this is a proof that the item is actually made of gold. However, there are many other metals that are non-magnetic, which can also be plated with gold and will not react to a magnet.

• The best way to determine the purity of a gold item is to test it with acid and also make sure that the piece is not made of another metal covered with a thin layer of gold.

Conclusion

There are many variations in the color of gold, ranging from white through to deepest red. Pure gold is a deep golden yellow orange. In its purest state it is very soft and although this makes it very easy to work with, for everyday use a harder metal is needed. Pure gold is therefore combined with a cheaper base metal to form an alloy. Copper or silver are commonly used in combination with gold to strengthen it. Thus what is commonly referred to as white gold has a high proportion of silver in the alloy. Similarly red gold contains a lot of copper in the alloy.

Also Read: ULIP vs SIP