Talk:Nines (notation)

Refining and testing procedures for 4N gold
what about four 9s of Gold? i.e. 999.9 pure gold? Can anyone help me in finding out the difference between 999 and 999.9 gold. I know that the difference is 0.09% purity difference. But I would like to know the refining procedures and testing procedures between these two purities. — Preceding unsigned comment added by 122.169.141.80 (talk) 15:05, 2 April 2008 (UTC)