Thanks Chris, the granite slab is a grave marker that wasn't used.... I purchased it from the local shop, it's about 3.5 or 4 inches thick. The rest of the bench top is made from "area board", some call it "puck board". It's available in different thicknesses, it's basiclly hard plastic. My knife is not damaged by it, not does it cut too deep into it either. I dn't mind using it at all. The cutting table in the middle of the shop is also covered with the same stuff.