18ct vs 9ct

Most people are aware that you get different carats of gold but if faced with a choice which one should you choose? Pure gold is is a beautiful rich yellow metal highly sought after by humans from the beginning of time. Pure gold is a soft but hard wearing metal that is not really suitable for the manufacture of most jewellery pieces. In some cultures people prefer pure gold or either very close to pure gold, like 22ct gold. Unfortunately they have to pay a price for this financially by making pieces extremely thick and heavy to add strength to the design so they don’t get pushed out of shape when worn.

In the jewellery trade pure gold is alloyed with other metals to add strength and hardness. Depending on the amount of alloys added to the gold will determine the carat. 18ct is 18 parts pure gold or 75%, therefore the stamp 750 inside many jewellery pieces. 9ct gold is 9 parts pure gold or 37.5% pure, therefore the stamp 375 found inside many jewellery pieces.Customers ask us on a daily basis is 9ct more durable than 18ct gold? The answer is a simple no. The reason people believe 9ct gold to be more durable than 18ct gold is simply because there is a confusion between the term “hardness” and “durability”. This brings us to the point that hardness and durability are not one and the same thing. To give a simple example, a glass ball is harder than a rubber ball. Try throwing each onto a hard surface. The glass ball will break, but the rubber ball will bounce and remain intact, because the rubber ball is more durable than the glass one. The glass ball breaks because it is brittle. In the same way, metal alloy can also be brittle, and 9 hard carat gold alloys tend to be slightly brittle, whereas 18 carat gold alloys tend to be more resilient. When you look at 18ct alloys they are almost completely resistant to chemical attack in normal use, whereas 9ct alloys are much less resistant and will go dull or even black when exposed to certain chemicals. 9ct gold is clearly the harder material when compared to 18ct gold but it is this hardness that reduces its durability when it comes to everyday knocks and wear and tear. Any Jewellery sales person who tells you 9ct is more durable than 18ct gold is either leading you astray or like the bigger population simply does not understand the difference between “hardness” and “durability”.