It was dug and finn ring was made from gernam silver, as say to me digger
I ask many collectors and no one saw it type ring in iron
I dont trust in iron )))
I wrote it above.
The exercise for 2015 to find one in iron....and i am pretty sure too...there is none because all this rings are made from this alloy.
If this dug ring on your pic is a real period one and is this alloy too, so most possibly all (or most) rings to this time were made from this material.