June 30, 2012 what is m600 in terms of silver? 1 M600 is stamped on the bottom of my antique silver set. Is that weight, or purity? Tags: m600, Silver, terms. Filed under Silver Antiques by admin on Jun 30th, 2012. Facebook Google+ Twitter Pinterest Email Print Delicious Digg Fark Google Instapaper LinkedIn MySpace Newsvine Pocket Readability Reddit StumbleUpon Tumblr Yahoo! Related Posts What is the difference between silver tone, sterling silver and stainless steel in terms of quality? Comments on what is m600 in terms of silver? June 30, 2012 Ron @ 8:54 pm It is a measure of it’s purity it means that the silver set is an alloy of silver and some other metal usually copper, the M600 indicates that there are 600 parts of silver in a 1000 parts of the alloy.