Some early humans used chert. Some used flint. The main reason was availability. . Both types of rock are amenable to flaking which is how early humans made stone tools. They could be made into scrapers, arrowheads, or spear points. And both types of rock can be used to start fires - so they were handy to have on the trail.
-Answered by priyanshu kumar On 20 October 2019:04:04:25 PM