how to check gold purity?
Hi,
When I first went to buy gold, I also didn’t know how to check its purity, but I learned a simple way. The easiest method is to look for the hallmark stamp on the jewelry, usually written as 22K, 18K, or 24K. This stamp is given by the Bureau of Indian Standards (BIS) in India, and it ensures that the gold is genuine and of the purity mentioned.
Gold purity can be checked using several other reliable methods, here are the some of the common ways:
BIS Hallmark
In India, gold items certified by the Bureau of Indian Standards (BIS) carry a hallmark. This includes the BIS logo, purity mark (like 916 for 22k), a unique HUID code, and the year of hallmarking. Always look for this stamp to ensure authenticity.
Acid Test
Jewelers often use nitric acid on a small scratch of the gold. The reaction shows the karat. While quick, this method may damage the piece if not done carefully.
Magnet Test
Gold is non-magnetic. If your jewelry is attracted to a magnet, it likely contains other metals. This test is simple but only helps detect fake gold, not its exact purity.
Density Test
Pure gold has a density of about 19.3 g/cm³. By weighing the item and measuring its water displacement, you can calculate density to estimate purity. This works best for solid pieces.
Electronic Testing
Portable electronic testers apply an electric charge to gold and measure conductivity. They can quickly identify whether gold is 14k, 18k, etc., but may not provide exact fineness.
Fire Assay
The most accurate method, also called the “gold standard” for purity testing. It involves melting and analyzing the gold but destroys a small portion in the process.