Flake tools

These tools could easily cut animal hide and other materials and so were often used in butchering and hide working. In order to make these very sharp flake tools, special kinds of stone had to be found. Usually basalt, chert and especially obsidian (the black glassy rock) were used because of the ability of the rock to fracture. Sometimes the people had to travel far to find the right kind of stone to make these tools. Do you think it's possible that people would trade for the valuable stones?