GoldQuestions
Gold purity, karat, and fineness
Gold purity describes how much gold is present compared with other metals, using terms such as carat or fineness.
Last reviewed: 2026-06-01
How purity is described
Gold purity describes how much of an item is gold compared with other metals. Carat language divides purity into 24 parts, so 24 carat is treated as pure gold in everyday usage, 22 carat contains 22 parts gold out of 24, and 18 carat contains 18 parts gold out of 24. Fineness expresses the same idea in parts per thousand, such as 999 for fine gold, 916 for 22 carat, and 750 for 18 carat. Bullion buyers usually see fineness because it is more precise for metal-value calculations.
Why bullion uses high purity
Investment bars and modern bullion coins often use high-purity gold because the product is intended to track metal content closely. Some recognised coins, including Sovereigns, use 22 carat gold because alloying improves durability while the fine-gold content remains defined. Jewellery uses a wider range of purities because colour, strength, wear resistance, and design matter. A lower carat item can be legitimate gold, but it contains less gold per gram than a higher carat item.
How purity affects value checks
Metal value depends on gross weight and purity. A 10 gram 9 carat item does not contain 10 grams of gold; it contains a lower fine-gold amount after adjusting for purity. This matters when comparing bullion, scrap, jewellery, and coins. Readers should check whether a quoted weight is gross item weight or fine metal weight, and whether the product description uses carat, fineness, or percentage. Misreading purity can lead to poor comparisons.
Key points
Carat and fineness are two ways to describe gold purity. 999 gold is high-purity bullion, while 916 is associated with 22 carat gold and 750 with 18 carat gold. Lower purity does not mean fake, but it changes metal value. Bullion comparisons should focus on fine-gold content, not just gross weight. Any unclear mark or claim should be checked before relying on it.
Educational disclaimer
This guide is educational only and is not financial, investment, tax, legal, or personal advice.
FAQs
Is 22 carat pure gold?
No. 22 carat gold contains a high proportion of gold but also includes other metals.
What does 999 gold mean?
It usually means 999 parts gold per 1,000 parts metal.
Does higher purity always mean better?
Not necessarily. The right comparison depends on purpose, durability, price, and resale context.
How do I compare 22 carat and 24 carat gold?
Compare the fine-gold content, not just the gross weight. A 22 carat item contains less gold per gram than a 24 carat item.