Both of those rocks look like extremely weathered pieces of granite or similar to me. The flat, black shiny surfaces are probably biotite mica, a clay mineral, which due to the large grain size indicates a slow cooling igneous rock.
This rock is rounded, as are mountain ranges formed from granite. Mountain ranges comprised of metamorphic and sedimentary rocks tend to be more layered and jagged.
This from my geology degree over 30 years ago... there are people on here way more knowledgeable. But if this is from a rock scarce area then maybe any piece of hard rock would have been used as a tool, without having the luxury of available flint or the like?