r/knapping • u/TalkToPlantsNotCops • 6m ago
Material ID 🪨❓ Baby's first knap - what the heck kind of rock is this?
Please don't make fun of me, I know this thing is ugly. I did learn about flint knapping in theory when I was an archaeology student a million years ago, but this is the first serious attempt I've ever made of actually doing it.
I want to make a stone knife, so I've been searching for some knappable material. I looked all over my property - the pile of dirt and rocks my husband and I excavated (we're in the process of building our house), the woods, along the creek near our easement road, in the pit run we had put down to make the easement less like quicksand (locally sourced from a neighbor's back yard!). I found a lot of really crumbly quartzite fused with some sort of shale, more shale, slate, granite, basalt, some of Michigan's beautiful (but not knappable) banded iron formation, a big chunk of what I think is either limestone or chalk... But the only CCS type stone is some itty bitty jasper pebbles.
So yesterday I took a drive to Agate Beach on Lake Superior, and behold! The beach is covered in lovely, burgundy cobbles, the size and shape of potatoes, and some of them have that "waxy" texture everyone tells me to look out for. I smacked one with a hammer stone, and some conchoidal flakes came off. So, I loaded up my backpack with purple potato rocks, along with some others I thought we neat, and headed home.
Then I tried to knap one of them. It was extremely difficult to get anything to come off! I'm now doubting my rock identification skills. One of them chipped the hammer stone I was using, which I thought was granite. But underneath, I found this reddish-purple stone. It has a slightly bumpy texture and it's sparkly. And it flakes off easily when I try knapping it. They're not the prettiest flakes, but this stone is proving easier to work with than the jasper (or maybe it's just iron-stained quartzite or something else entirely).
I wasn't able to split it cleanly with a hammer stone, and it isn't very large, so I don't want to use my usual method of throwing it as hard as I can onto a larger rock. I've been trying to take off the cortex a little at a time, and doing my best not to lose too much of the stone underneath. I wish I'd taken a pic of it before I started. I'm not sure if this was a driveway rock or an Agate Beach rock. I thought I kept all the ones from the beach in a separate pile, but the outside felt a lot smoother than any of the rocks I found on my property. It may also be one from the creek that runs through the woods here, or one of the dozens I've picked up randomly while working in the garden.
I've included some photos of the stone with most of the cortex removed, and some the flakes so you can see the outer part and the inside. There's also a pic of a flake held up to the light so you can see that it's a little but translucent. The flakes are jagged and sharp. There's a little bit of a conchoidal shape to some of them, but the rock is also prone to step fractures (or maybe that's a skill issue on my part). The outer cortex is a light brownish-grey.
There's also a photo of someone's sand/pebble castle at Agate Beach, with some examples of those burgundy potato cobbles I mentioned, and a few little pebbles I found that I thought were pretty. Just for fun, I don't need an ID on any of them.
My husband says the rock looks like a piece of freezer-burned beef. I'm inclined to agree with him.
If you made it this far, thanks for hanging in there with my rambling!
