Pure gold is too soft to be used in everyday jewellery, so other metals are mixed with the pure gold to create a metal suitable for everyday wear. 18ct gold is made up of 75% pure gold and 25% of other metals. Platinum is alloyed with other metals for strength and workability rather than colour. The platinum used in our jewellery is 95% platinum alloyed with 5% copper. Read a little more about the differences here.