24ct gold is the ultimate gold carat, it doesn't go any higher than this. It's the purest form and consists of 99.9% gold. It is naturally yellow and highly valuable, but very soft and malleable, so it is not usually used to make fine jewellery or intricate objects. It's usually mix with a metal like copper or silver to make jewellery. Each carat indicates 1/24th of the whole.
18ct gold contains 75% gold, with the rest made up of other more durable metal alloys used to add colour and strength. White metals will be added to create white gold with copper added to create rose gold. 18ct yellow gold is appreciated for its radiance and is much warmer and brighter in tone than 14ct and 9ct gold – but with its high percentage of gold, it still comes at a higher price.
VARIOUS COLOURS OF GOLD
24ct gold has the natural warm colour of pure gold and its colour cannot be changed without changing the purity of gold to less than 24ct. Other colours of gold can be made by changing the composition of the alloy in the making of the jewellery:
- Rose gold is made by adding more copper in the alloy composition of the gold
- White gold is achieved by adding nickel or palladium