Which Gold is harder? 9ct or 18ct? - blog post image

Which Gold is harder? 9ct or 18ct?

It seems most people that have been researching wedding rings, whether on the net or talking to shop staff, are told that 9ct is a harder metal than 18ct. However this is only half true, therefore only right 50% of the time. 

Yes, the carat of the gold makes a difference, although the colour of the gold must be taken into consideration to fully understand this precious metal and choose the right alloy for you. The colour of the gold is determined by the other metals that are mixed with fine gold to get 9ct, 14ct and 18ct alloys (an alloy is a mixture of 2 or more metals). Gold, of course, is the base metal, 24ct being pure gold, 18ct is 75% pure gold 25% other metal (hall marked 750) 14ct is 58.5% fine gold 41.5% other (hall marked 585) and 9ct is 37.5% fine gold and 62.5% other (hall marked 375). 

It is the other metal that is added that determines both the hardness and the colour of the end result. It is much the same as mixing paint.  When making yellow gold or rose gold we add silver and copper, the more copper we add the 'rosier' the gold will become, and the more silver we add the 'whiter' the metal will become, and as copper is harder than silver the rosier the gold, the harder it becomes, which brings us back to the original question which is hardest?

In yellow gold, the 9ct alloy is a harder metal as there is more copper in 9ct than there is in 18ct therefore the 9ct yellow is a harder metal, however in white gold there is a lot more silver in the alloy as the silver whitens the colour, it's also a softer metal, therefore in 9ct there is a lot more silver to gold ratio so it becomes a softer alloy than the 18ct white gold alloy.

To sum up, 9ct yellow is harder than 18ct yellow as there is more copper in the alloy, and in the white gold, 18ct white is the harder metal as the 9ct white has a lot more silver, which is soft. So when choosing the best metal for you, first decide whether you want white, yellow or rose, and then decide whether the hardness is of concern.

All the rings I make are made to last and able to have alterations done to them without being concerned that they will suffer, taking into consideration how they will be worn and how often. I don't want you to be worried your ring won't last or become misshapen. I make every ring with the thought that if anything needs to be done to it I will be the one doing it, and I don't want to work on a ring that hasn't been made well enough to be sized and altered as life changes.