Joey, I think you would be wasting your time with the slate, comes off in layers. When I first started obsidian seemed pretty brittle but I did better with dacite which also is a volcanic type of glass but seems to be tougher than obsidian, an it,s not real pricey. Craig is good to deal with an I,m real happy with the stuff I get from Eric,s Rocks also. Don,t give up It just takes time an alot of rock. Remember this is a hobby of tonnage. Good Luck Bob