Quote Originally Posted by adrspach View Post
Can you try to scratch the stone with clean copper wire? Does it gouges the stone or not. What is the size of the stone?
It is 7.25 by 1.25'' IIRC. I don't have any copper wire, but I scratched the stone with a 2 pence coin which is plated in copper and left a white scratch. Different story when whetted. The stone removed the copper rather quickly, turning the water dark grey. Not slurry, as the slurry is a white colour.