2-Year U.S. Treasury Note Continuous Contract $103.508-0.027-0.03% 5-Year U.S. Treasury Note Continuous Contract $107.938-0.078-0.07% 10-Year U.S. Treasury Note Continuous Contract $111.031-0.141 ...

This means that if you buy 18K gold, 18 of the 24 parts will be pure gold and the rest will be a 50:50 mix of copper and silver because the purest gold is too soft to be used in jewellery.