Platinum
Platinum is the most precious of all metals. The most appealing characteristic of platinum is its durability due to its high resistance to corrosion. As it is a pure white metal, jewellery made from platinum will not change colour. Most platinum jewellery is 95% pure platinum and 5% iridium alloy.
Gold
Pure gold is measured as 24 karats, and is too soft for everyday wear. It is alloyed with a mixture of other metals like silver, copper, nickel, and zinc to give it strength and durability. The colour of gold is determined by the type and percentage of metal alloys added. 18 karat gold is a mixture of 75% pure gold with 25% other metal alloy.
White Gold
White gold is a mixture of pure gold with white metals, such as pladium or silver. For instance, 18 karat white gold contains 75% gold and 25% of white metals. Given the composition, jewellery made from these metals has a slight yellow tinge. To enhance the whiteness, almost all white gold is plated with a shiny white metal called rhodium. Through ordinary wear, this rhodium plating may wear off over time, revealing the original metal colour. Re-plating may be done by a jeweller to restore the whiteness of the jewellery.
Rose Gold
Rose gold gets its beautiful pink colour from combining gold with a larger proportion of copper in the metal alloy.