Just thought I would share b/c I am still excited about it myself but I went Saturday to Lowes and while looking for frag base material I ran across three damages 1'x1' tiles with 1"x1" patterns of smaller tiles so I asked the guy... "Would you take any off of these if I were to buy them?" They were almost 9 dollar a piece new per sheet and the guy came back with "I'll give em to ya for a dollar a piece" ... I pounced. almost 400 tiles for 3 dollars... Cant beat that anywhere... LOL
90% are natural slate. They are all natural as far as I can tell. All the ones I have broken have been anyway.
I was a bit worried about the glue on the back side though. As I tore them off there was a nice little grid pattern on the back of them. I let them soak in a bucket of used tank water for the day and mixed them up good. within a couple of hours it came right off when I rubbed them with a towel.