How gold purity affects its value

Karat in plain terms

Karat measures gold purity on a scale of 24. A 24-karat item is almost entirely gold, a 22-karat item is 22 parts gold out of 24, and an 18-karat item is 18 parts out of 24. The remaining parts are other metals that make the jewellery harder and more durable.

That is why a 10 gram chain in 18 karat contains less gold than a 10 gram chain in 22 karat, even though both weigh the same on a scale.

Purity expressed as a number

You may also see purity written as a fineness number, such as 916 for 22 karat, or 750 for 18 karat. They mean the same thing, shown in parts per thousand.

What this means when you sell

• Higher purity means a higher value per gram.
• Purity is checked on the day, because wear, repair and solder can change the actual gold content of an older piece.
• Ask to see the purity result for each piece, not only a final figure.