How much silver is contained in typical 9ct gold jewellery?

9ct gold for example must contain 375 parts per thousand of pure gold, while 18ct gold must contain 750 parts per thousand. For an item to be described as ‘Sterling Silver’ it must contain 925 parts per thousand of silver, while platinum, the purest of the three, most commonly contains 950 per thousand of platinum. There are six commonly used ‘finenesses’ of gold in the UK, four finenesses of silver and four of platinum.