Sharp and gritty? Can that work?

[Prarie Bowyer]

I should have gotten a pic of this rock.  There is tons of it near me below a dam.  It's red verging on black on the outside and grey and silvery sparkly on the inside.  It's kinda gritty looking BUT the stuff seems to fracture nicely.  Any idea what that might be and if it's worth bothering with to knapp?

I picked up a couple of pieces and it tends to make long sharp(ish) edges along it's fractures.  I broke a couple pieces togeather and I think it would knapp but it has a texture like sandstone on the inside only harder.

[Jimbob]

Your right pics would help alot but Id say that if its free its always worth knapping!!   Even if its just somthing to keep you busy until you can get some other stuff.

[bushman]

Pictures would help a lot. If you do get a chances to take some pictures I would like to see them. It sounds like a type of rock that I got all around here. If it is, you can try knapping it but its hard, also the fakes you nock off aren’t good for much, they snap in half way to easily. It will make some crude hand axes thou.
Bushman

[cowboy]

sounds like a quartzite type rock. Hard to knap, heat does nothing to it. But you can make crude tools from it to keep ya busy as afore mentioned until you can get some good stuff .