Which is better - 9ct or 18ct gold?

Posted by Justine Donaldson on

This is a question we very often get asked and many people have heard the myth that 9ct is better because it is harder.  Is this correct?  Well no – it’s a myth! 18ct gold is definitely the better metal, especially for your engagement and wedding ring that you want to last a lifetime.  Let me explain why ….

Firstly lets look at the hardness factor.  Yes, 9ct gold is ever so slightly harder, but that doesn’t mean it necessarily wears better or has greater longevity than 18ct gold.  There are several other factors which to contribute to making 18ct the better metal which will stand up to everyday wear better than 9ct and tend to look better as it ages over the years.

18ct has a much higher pure gold content than 9ct – twice as much in fact!  18ct contains 75% fine gold whereas 9ct is only 37.5% fine gold.  Because of this, all the most desirable attributes of gold, which make it so ideal for jewellery making, are more prominent in 18ct gold.

Chart showing comparison of gold content in 9ct and 18ct gold

18ct gold is more DUCTILE than 9ct.  This means it can be moulded into different shapes or drawn down into thin wire without cracking.  It is also more MALLEABLE than 9ct which means it has the ability to be worked or hammered without breaking.  Because 9ct gold is both less ductile and less malleable than 18ct, it is more likely to become brittle and crack over years of wear and tear.

18ct is also a denser metal, it may be slightly softer but because of its density it will outlast 9ct every time!  9ct is more porous (less dense) so is more susceptible to being attacked by everyday household agents such as lemon juice, vinegar, detergents and – in particular – chlorine bleach, which can cause the surface of 9ct gold jewellery to become pitted and abraded more quickly.

18ct gold is a far nicer colour because of its higher gold content.  It has a rich yellow look compared to 9ct which tends to be a lighter yellow.

18ct gold stamp inside band of ring

So, in summary – Yes 9ct is harder but No – it is not better!  18ct gold is the better metal and will stand up better to wear and tear over a lifetime of use because of its superior density, malleability, and ductility.  So when choosing an engagement or wedding ring that you’ll wear for a lifetime always choose 18ct gold if your budget can possibly allow it.  If not, don’t worry – 9ct gold is still a great metal for jewellery and is much harder-wearing than cheaper options like silver for instance, it may just require a little more maintenance over the years, especially if it’s an item you want to wear every day.

One final point to keep in mind if you’re wearing more than one ring together on the same finger it is best to stick to the same metal.  Ie if you have an 18ct gold engagement ring then choose an 18ct wedding ring and eternity ring.  Likewise if your engagement ring is 9ct then stick with 9ct for any other rings you’ll wear next to it.

All this may leave you asking the question: Well what carat gold is my jewellery and how do I tell?  Keep an eye out for our next blog post which will explain the different gold carats further and show you how to read and understand the stamps on your jewellery to identify the caratage.

Thanks for reading our blog!

Wedding ring specialists


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