Burt is correct Romeo 'bout findin these in CW sites. I have dug 3 so far.The story i have found is that during the war folks jist couldn't afford solid gold so there were rings made of other metals such as brass or copper, I even dug one made of iron,and they were then plated...cost much less than solid.There is also another aspect here, There were rings made of rose gold that will in fact loose thier color over the years in the dirt. If these are properly cleaned by a good jeweler they will get thier color back.
As you can see in the pic, mine is stamped 18K but looks colorless. I have found two of these same rings at the same site.
I even have one that is made of two metals, appears to be gold and copper, with the forementioned surrounded buy the later.