About the type of stone, I think it was part of some I got from Waco, TX. It was too difficult to be a practical material until I cooked it. First time it was cooked at 450 X 12 hrs. Second time it was cooked at 480 X 14 hrs, and it works very well. I had a hard time getting the flake scars to show, and those photos make it look like the flake scars are pretty deep, but actually it is hard to tell where the scar lines are. I snapped the second piece in half after I got it thin. Thanks for the compliments.
WA