Stone ID

Dan Rowlett
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Dan Rowlett
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Joined: September 1st, 2017, 7:33 pm

July 9th, 2018, 2:58 pm #1

Does anyone know what kind of stone this is? I picked it up in the Springfield MO area.
I know it's a type of chert but that's all. It doesn't work very well raw, I'm going to try cooking it. In " The Art of Flintknapping" Its suggested to heat MO cherts to 550 to 600 degrees. I have a turkey roaster that goes to 550 so I will see how it comes out.
I'm open to suggestions from anyone who has cooked this kind of rock. I have little to no experience myself with heat treating rock

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freeze cracked
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freeze cracked
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Joined: October 30th, 2012, 2:24 am

July 9th, 2018, 3:02 pm #2

looks like springfield burlington. some of that is great heated, and some has too much chalk and crystals in it. google heat treating burlington chert and follow the recipes and hope the 550 changes it some. when i work burlington raw, it's almost always fresh out of the ground so it has enough moisture in it to assist. some of that stuff gets fairly unworkable raw once it's dried out. and the chalky stuff isn't always worth even attempting to work. 
i dream of a better world in which chickens can cross roads without having their motives questioned.
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Dan Rowlett
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Dan Rowlett
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July 9th, 2018, 3:42 pm #3

Thanks Freeze Cracked, I'm hoping it will be workable once heated. My brother has 25 acres just south of Springfield. This rock is everywhere on his place. Be a great source of stone if it will behave properly.
He has had some recent dozer work done and exposed a lot of stone. Most was fractured and chalky but every now and then a piece seemed like it might be ok.
I was able to make a rough preform out of one piece, raw, so we will see after heating it

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freeze cracked
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freeze cracked
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July 9th, 2018, 4:55 pm #4

jim redfearn knaps a lot of springfield burlington. some of it is great stuff. if the flakes run smooth and normal-looking but the rock is just tough, then it probably will be nice when heated. if the stuff is grainy, chalky, crystally, or cracked up, it might be best to look elsewhere in the area and test hit stuff till you find good material. it's around there somewhere. some folks look for rock in creeks. 
i dream of a better world in which chickens can cross roads without having their motives questioned.
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Dan Rowlett
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Dan Rowlett
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July 9th, 2018, 5:02 pm #5

Ok, thank you for the info

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CurtisSmith
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Joined: December 14th, 2006, 6:31 pm

July 9th, 2018, 7:06 pm #6

I concur with Burlington.   Some of that Burlington works well raw too.  This is some I collected from Springfield and knapped raw.  If you want to heat treat it most does well between 550 to 650. 20170926_103547.jpg
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Dan Rowlett
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Dan Rowlett
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July 9th, 2018, 8:00 pm #7

Thanks Curtis.
Some of what I found has varying textures and colors, like the point you show.
In your experience does heating Burlington improve its knapability?

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CurtisSmith
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July 9th, 2018, 10:17 pm #8

Yes. Heat treating Burlington definitely makes it knap easier.  Makes it glassy and some even gets some color.  Most modern knappers prefer it heat treated. 
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Dan Rowlett
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Dan Rowlett
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July 9th, 2018, 10:21 pm #9

Curtis, thanks for the help.

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nogie1717
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July 12th, 2018, 4:59 pm #10

I purchased some Burlington from Curtis that I think was from that batch he collected in the Springfield area.  The reason I mention it is that throwing it in the turkey roaster and getting it to the 550 or so didn't gloss it up like some of the cooked Burlington that I've come across, but it made it knap considerably easier and did bring out some pinkish tones.  FWIW.
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Dan Rowlett
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Dan Rowlett
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July 14th, 2018, 3:36 am #11

nogie1717 wrote:I purchased some Burlington from Curtis that I think was from that batch he collected in the Springfield area.  The reason I mention it is that throwing it in the turkey roaster and getting it to the 550 or so didn't gloss it up like some of the cooked Burlington that I've come across, but it made it knap considerably easier and did bring out some pinkish tones.  FWIW.
Took my samples out of the turkey roaster today. My batch turned out as you described except there was no color change. No gloss, no color, but did flake correctly and considerably easier. Made the right sound when the flakes separated as well. My toaster only goes to 450 on the dial. I was mistaken in my earlier posts when I said it went to 550. I think it just needs more heat. Guess I'm kiln shopping now.

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nogie1717
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July 14th, 2018, 3:39 am #12

Does your roaster have an inner liner? I took mine out and insulated the top cover. This helps mine reach the 565 mark when the dial only goes to 500. Glad to see you got some change!


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Dan Rowlett
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Dan Rowlett
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July 14th, 2018, 4:16 am #13

nogie1717 wrote:Does your roaster have an inner liner? I took mine out and insulated the top cover. This helps mine reach the 565 mark when the dial only goes to 500. Glad to see you got some change!


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Yes it came with a liner but I took it out. I also insulated the lid. I really dont know how hot it actually gets, I've only cooked a couple batches of rock and never put a thermometer in it to see. The dial says 450.
I did fill it with sand. I cooked a couple pieces of Texas rock in the same batch, that went in grainy and hard to flake. They came out glossy and flaked well though. Here's a pic.

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nogie1717
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July 14th, 2018, 4:39 pm #14

I finally bought a thermometer that goes up to 550.  It governors out when I temp after 12 hours at max temp.  Based on the rate of increase going up to 550, I'm guessing that I'm at about 575 in the turkey roaster.

The thermometer I got is a digital one that I bought for about $10 in the Walmart grilling section.  Texas rock is fun with a turkey roast because it doesn't need the higher temps (in a lot of cases).  
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Dan Rowlett
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Dan Rowlett
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July 14th, 2018, 5:04 pm #15

nogie1717 wrote:I finally bought a thermometer that goes up to 550.  It governors out when I temp after 12 hours at max temp.  Based on the rate of increase going up to 550, I'm guessing that I'm at about 575 in the turkey roaster.

The thermometer I got is a digital one that I bought for about $10 in the Walmart grilling section.  Texas rock is fun with a turkey roast because it doesn't need the higher temps (in a lot of cases).  
Guess I should get a thermometer then

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