Keith, I wonder too, nice stone.. I believe mine is Belgium Ardennes rubble stone, but then in its raw form, brought to my place in the ice ages.. The ardenne rock for sale in the regular trade as in garden centres and pavement suppliers then the stones are tumbled in a big barrel (no idea how that process realy is called in english) to make it smoother. Then the color changes somewhat to gray and the marble effect goes a bit away. But raw cut is more black and more distinct marbled. That stone is very commen in my area because i live not far from the Belgium Ardennes. It's often used in aquascapes and fish tanks most commonly in cichlids tanks, like this picture, but this is also tumbled garden centre stone with some hand cut pieces among them. if you handcut it it can be razor sharp edged. the stone in the above scapefu scape does look simmular, but is clearly a bit different in texture. more dimpled.