thumb|250px|Stone slab in east-central California used to grind acorns In archaeology, a grinding slab is a ground stone artifact generally used to grind plant materials into usable size, though some slabs were used to shape other ground stone artifacts. Some grinding stones are portable; others are not and, in fact, may be part of a stone outcropping.
thumb|250px|stone slab in east-central california used to grind acorns in archaeology a grinding slab is a ground stone artifact generally used to grind plant materials into usable size though some slabs were used to shape other ground stone artifacts some grinding stones are portable; others are not and in fact may be part of a stone outcropping