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What is the Difference Between 9ct and 18ct Gold

The Main Differences Between 9ct and 18ct Gold.

Fine gold content:

• 18 carat gold contains twice as much fine gold by proportion (750ppt vs 375ppt)

• 18 carat gold is approximately 40% heavier.

• 18 carat gold contains over 2.6 times as much fine gold as a 9 carat product of the same size/volume. That is to say, don’t expect that if you have two identical items in 9 and 18 carat gold, the 18 carat one has twice as much gold, this is not the case.

Other properties:

• Tarnish resistance – 18 carat gold is more resistant to tarnishing and other chemical attack than 9 carat gold. This is because silver and copper, which constitute a larger proportion of 9 carat gold, oxidises more readily than gold.

• Hardness – An issue on which there is much discussion. It is often claimed that 9 carat gold is harder than 18 carat, but this does not mean it is more durable. Gold rings can give many years of wear – a ‘soft’ 22 carat ring can easily last for more than 50 years, and the wearer can appreciate the fine colour and lustre of almost fine gold for the whole of that time!

By Bella Pritchard-Barrett

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