Author Topic: Can anyone tell me if this rock is chert?  (Read 2891 times)

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Sleep Junkie

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Can anyone tell me if this rock is chert?
« on: July 14, 2009, 03:41:09 am »
Hi all,

I am very interested in primitive archery and I frequently lurk on this site.  I could spend hours on hours reading through all of the interesting information that you guys have managed to accumulate.  However, today is my first post and I need some help.  I live in Juniata County here in central Pennsylvania and I know that there is supposed to chert in the area.  At least that is what i have read.  However, I have never seen it close up and in person so I am at a loss when it comes to identifying it   Seeing it in a picture is one thing, but being able to hold it so you can feel the texture and weight really makes a difference.  Well, I was hiking today and I came across some stones which may or may not be chert, so I picked it up and put it my pack.  I figured that I could take some pics, post em here and you guys could help me to identify it.  Now keep in mind that I am new to this, so don't laugh too hard if the stone I have collected is granite or something.  haha  I do want to start trying to knap though and it would be very helpful if I had a supply of stuff to practice on.

This first pic is of the outside of the stone.  This side is what the entire thing looked like before I broke it in half.  The grey colored side of the stone is the inside.  This stuff is pretty hard.  I took another stone from the area and hammered on it to see how easily it chipped.  I was able to break chips off, but as I have never knapped before, I don't know how it is supposed to act or how hard you have to hammer on it.  So what do you guys think?  Is this chert or am I way off?



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« Last Edit: July 14, 2009, 04:07:00 am by Sleep Junkie »

Offline Hillbilly

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Re: Can anyone tell me if this rock is chert?
« Reply #1 on: July 14, 2009, 07:11:01 am »
Looks like limestone/dolomite or a really low-grade chert. Some of the higher-grade silicious limestone is knappable, but it ain't easy. If you have limestone, you've probably got chert somewhere in the area.
Smoky Mountains, NC

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Offline cowboy

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Re: Can anyone tell me if this rock is chert?
« Reply #2 on: July 14, 2009, 07:16:33 am »
I'm not sure what's in that part of the world but that looks to be closer to granite than chert. Need to find something that breaks cleaner, well I can't even say that. Something like Normanskill, rhyolite, quartzite, horse creek chert from KY is all grainy inside but works good with heat treating. You might try some glass to keep ya busy while your on the hunt for rock..
When you come upon a track or trail you do not know, follow it to the point of knowing.

Offline mullet

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Re: Can anyone tell me if this rock is chert?
« Reply #3 on: July 14, 2009, 08:20:01 am »
  looks like Kniess.
Lakeland, Florida
 If you have to pull the trigger, is it really archery?

Offline Hillbilly

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Re: Can anyone tell me if this rock is chert?
« Reply #4 on: July 14, 2009, 11:20:07 am »
There's a lot of that limestone just like that in eastern TN. That's actually what I mostly learned percussion on, but I wouldn't wish it on anybody else.
Smoky Mountains, NC

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Offline richpierce

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Re: Can anyone tell me if this rock is chert?
« Reply #5 on: July 14, 2009, 11:57:07 am »
It is probably chert but not knappable.  Some stuff is "nubbly" inside.  yes, it's silica and hard, but won't break smoothly.  I say it's a form of shert because the cortex or rind is limestone and the inside is not.  Keep looking in that area.  There's often good and junk stuff mixed together with most of it low grade.  Try looking in streambeds on gravel bars if you have any.

Offline billy

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Re: Can anyone tell me if this rock is chert?
« Reply #6 on: July 15, 2009, 01:08:44 am »
looks like $&it to me!!!  Hahaha
Marietta, Georgia

Sleep Junkie

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Re: Can anyone tell me if this rock is chert?
« Reply #7 on: July 15, 2009, 01:43:28 pm »
Thanks guys for all the helpful replies. 

Hillbilly - I know we have some limestone mines or quarries in the area, but none of them are used for commercial purposes.  At least not anymore, so they are hard to locate if you don't know where they are.  I guess I am going to have to do some asking around.

Cowboy - I didn't know that it could be heat treated.  Is that something you can do yourself or are the temperatures needed too high for someone to do in an oven?  I guess I will have to look it up.  I thought about trying to learn on glass, but as of yet, I have not come across anything that was thick enough.  I was thinking about heading to the local dump and looking to see if I can find some glass items that are of a thicker nature than the bottom of bottles.  Any suggestions on what glass objects are good to practice with?  I read somewhere that old toilets would work if you break them into smaller chunks.  Is that true?

Richpierce - I actually found this rock right along the edge of a stream bed.  I forget where, but at some point, I had read that stream beds are good places to look because all sorts of rocks get washed down stream. 

When you guys are out looking for chert, what is it exactly that you look for?  Or is it one of those things where once you find it for the first time, it just kinda jumps out at you from then on?  I remember when I first went out looking for sassafras root, I had a horrible time finding the first plant.  However, once I found the first one, the rest just seemed to jump out at me.  I don't know if any of you all have ever looked for it, but is a strange plant in that it has three different shaped leaves all on one plant.  Once I actually seen one up close, then I realize that they were all around me and I had just been overlooking them.  LOL

Offline DanaM

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Re: Can anyone tell me if this rock is chert?
« Reply #8 on: July 15, 2009, 01:53:54 pm »
Old TV tubes have nice thick glass, glass plates, and glass tiles, toilet tanks(thunderchert) work but are difficult, Find a glass shop
and see if they have scraps of 1/4" plate glass :)
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