JD, yep, flint, rhyolite, and especially quartz will break to a razor-sharp edge (at least the better grades of them, some of the grainier stuff won't get razor sharp.) I don't know how many times I've been knapping these materials and cut myself badly, but the flake that did it was so sharp that I didn't even realize I was cut until blood started dripping off my hand. I totally agree with your thoughts that no matter what point material you're hunting with, you should take the time and effort to get it as sharp as you possibly can before you shoot it at an animal. Sharpness isn't the only determining factor-point size and shape, durability, the way it's hafted, shaft and point weight all affect how a point will perform, but sharpness sure helps.