ID on some rock please

[bryan irwin]

found this rock today on the pee dee river it's black with shiney specks in it any one know what it is it flakes good if it works alright im going back and get some more.

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[arappaho]

yeah Bryan, that's some Porphyritic Rhyolite, and was one of the favorite materials of the abos around here.
There are outcroppings of it all thru the Uwharries. Good find and I'd go back for more.
Heat treatments don't help this stuff at all. What you see is what you get.
Joe

[bryan irwin]

thanks and didn't i get some ryolite from you at the nc knapp in.

[nugget]

Looks like neat stuff Bryan. I'm gonna have to get with you and help to tote a bunch of that out.

[arappaho]

That's totally possible, Bryan. I was there with a bunch of rock.
I hope you were able to get something out of whatever you got from me.
I must confess, tho, there was an atlatl maker named Bryan at the first NC Knap-in,
(he didn't make it to the last one), and I'm afraid I'm getting the two of you confused.
I hope to rectify that in the future.
And, for those of you trying to identify these rocks, Rhyolite is a generic term applied to
alot of the rock here in the Uwharries. It is very different from the rhyolite you see out west.
The full geologic name of that stuff you're finding is, Meta-sedimentary Porphyritic Rhyo-Dacite.
Now if that doesn't make you want to take a whack at it, I don't know what will.

But keep in mind, that you can't tell by looking at it how well it will knap. One outcrop will
work beautifully and another won't work at all. You've got to bust some in the field to know
if it's worth the tote home.

Happy Hunting,  Joe

[Hillbilly]

Some of that porphyritic rhyolite knaps really good, some of it is almost unknappable. Most knappers call it "speckled rhyolite", and the phenocrysts in it can be either feldspar, quartz, pyrite, or other stuff. I've seen some from on down the river in SC that has white specks when fresh that turn sulpher-yellow after they're exposed to the air for awhile. That looks like a pretty good grade, and should knap pretty good with hardwood or antler. Most of the Savannah River, Stanley, and Guilford points in central NC were made from that stuff.

[bryan irwin]

i found a place that has some that is blue green and black they built bridge peirs out of it and the river is full of it .

[nugget]

I am ready to go let me know when. 

[piper]

Me too

 Curt

[warhawk]

me too

[sailordad]

i dont know what it is
but i would hit it,heck i'll hit anything
even concrete if i get hard up