Carolina Rhyolite

[Weepingeyegorget]

Is silicified Shale and silicified Siltstone the same thing.. I always considered  rhyolite when tiny crystal where present in the material and silicified shale when its blue-green softer and no crystals are present..

[JoeM]

Yes, Lance, they are almost the same thing. Just got to figure in the "fissility" factor of shale.
The blue-green "softer" stuff is what we are calling the siltstone/mudstone/Argillite.
Scroll to the bottom of the this page, http://www.thudscave.com/petroglyphs/knappable.htm
Joe

[Butch Wilson]

Nice material in this plow busted point

You can see a little of the original color in the break.

[Bill]

Weepingeyegorget, the two materials are both metamorphosed sedimentary rocks, however they are miles apart in workability. Shale is a bedrock that varies in quality and fracture property. Shale mostly has a slatey type, rough grained, fissle fracture tendency and separates into sheets. Better qualities of more highly metamorphosed Shale can fracture somewhat chonchiodally and in the hands of a good Native American knapper, was workable.
Silicified Siltstone is highly metamorphosed, fine grained, and posesses excellent conchoidal fracture properties, similiar to Chalcedony (high quality Chert). This is great stuff and I have seen some great and beautiful points that were made out of it.

[bmart0693]

This was a very informational thread on the many types of rhyolite forms in NC.  It has many good links and knowledgeable people.  I found this very useful because I have this rock that I could not identify.  It was found in Yadkin County by my grandpa and I think he found it while plowing a field, back when there were no tractors.  It's patinated red because of the red clay dirt.  I had to break a piece off of it to see what the material is inside.  Inside it is a fine-grained, black coloration and it fractured conchoidally.  I also noticed very tiny crystals were present.   I really liked reading about the different forms of rhyolite on this posting so that I could get a good idea of what I have here.  Thanks for all the help gentlemen!

[bmart0693]

[QUOTE]CliffJ wrote:

Hi Cliff, the high quality transulent green stone you mentioned is actually a sedimentary rock that has been identified by Geologists as Green Silicified Siltstone. It is chert-like in workability and some awesome points have been found that were made out of it. Years ago I saw an incredibile Hardaway Dalton that, long ago, had been found at what is now the Town Creek Site.
There is another green translucent stone that has frequently been found in Stokes County, NC,and it is Moss Agate.
Picture from left to right, Hardaway Dalton, Hardaway side notch and Kirk Corner Notch; both Hardaways were made out of Moss Agate and the Kirk was made out of Green Scilified Siltstone. I took this picture in bright light to show the greater translucency of Moss Agate when compared to Green Scilicified Siltstone. GSS has the translucency of high a quality Chert (Calcedony) and the Moss Agate is extremely translucent like a high quality quartsite.

Hi Bill,
  Yes, that nice Kirk is made of the green material I was speaking about. Out of thousands of finds I've only found a few artifacts made of that fine material. It must have come from a small limited outcrop.  It doesn't show much patination at all. I've always thought of it as a high-grade rhyolite but the silicified siltstone title makes sense. Now, is the high-grade grey colored lithic also silicified siltstone- the one translucent on the edges?
  I can't see enough of the other 2 points because of the glare- but they look much different from the moss agate I've found, which is blue-yellow with moss specks in it. We don't see much of that either.
  I think the material you guys are talking bout is from Limerock.  I live bout 5 miles or less from the Limerock quarry.  It is a small outcrop right beside the river on the Yadkin side.  I've heard that quarry produced rare materials but never got to see them b/c they are hard to find.  I'm not 100% sure but my best guess for that material found in this local area would be from Limerock.  Check this reference out I found on the minerals produced from the Limerock quarry; there is one or two there that is translucent like of that point.  http://www.mindat.org/loc-194679.html

[vabowhunter77]

Hey cliff. thanks for posting on my knife point but i was wondering what type of point is that in your picture in the lower left corner. The brown one. Do you think its the same type as the pic im posting? Also what type of material do u think this is?

[utilized flake]

maybe a wills cove woodland point..,I don't know compared to the fact that its a killer~    David

[Hoss]

vabowhunter77 wrote:

Hey cliff. thanks for posting on my knife point but i was wondering what type of point is that in your picture in the lower left corner. The brown one. Do you think its the same type as the pic im posting? Also what type of material do u think this is?

  I know it wa sover five months ago but I think the question should have gone to Lance and not Cliff. Weepingeye posted the picture of a point similar to yours in the lower left.
I woulda called it a Savannah River point. Not sure how I missed the original question. I am just happy this thread was brought back to the top. It is a very informative thread

[Rock queen]

Rhyolite ?  A couple from my area.

[Butch Wilson]

Hey Rockqueen, looks like two different materials the one on the right looks just like the rhyolite I find here! If you go through this thread you will see that the term rhyolite covers a lot of material!
Thanks for posting!

[Rock queen]

The one on the left is probably silicified sandstone then

[Rock queen]

A couple more from here

[JoshinMO]

Nice Post Butch, Thanks for sharing!
Ours out here is usually maroon/brown but some also has a gray or "grey" ( :lol: ) appearance like some of that carolina rhyolite.

[carybreeef108]

Hi Josh. Do you have a pic of the maroon brown? I found a gorgeous maroon brown guilford (i think yuma style) in NC. Never saw that material before or since. Lots of steriped rhyolite, actually been digging at my house and finding hundreds of worked pieces, nothing earth shattering but still nice finds.

[NC_Stone_Collector]

Here are three frames from my collection, showing some examples of NC rhyolite. This material made Kirks, Stanleys, Guilfords, Archaic knives, Will Coves, Adenas and more; these are just a few types shown in my frames. Most have differing colors, ages -and- patinas, mainly due to their environment/climatic processes (temperature, rain, wind, and/or pressure); and there's other geological processes too. The three arrowheads at the bottom of the large frame are 3 personal finds of mine, from along the Yadkin River (2 Kirks & the Wills Cove). The others where found, generally closeby, in the NW to Central Piedmont region of NC.