The art of making arrowheads and stone projectile points is 'flint knapping.' There are a few people who still do this. I've played around with it with quartz. Inevitably, I end up with little specks of quartz, bleeding fingers and nothing resembling a projectile point in any way.
There absolutely was an art to finding the right kind of rocks. One of the cool things is, the fact that obsidian (volcanic glass), one of the best materials to make a cutting edge, has been found throughout the central plains. There are no volcanoes in the region, giving evidence to far-reaching trade from Mexico to the south and the southwestern US up through the United States. I teach Earth Science and am a total nerd!
I'm always on the lookout for arrowheads and spear points!