Artifacts Heated After Knapping

[ohiofinds 1]

Artifacts heated after knapping have at least four characteristics.
1.Color change , most materials turn pink or red depending on the amount of heat.
2. Surface Gloss , most materials become more glossy after heating.
3. Potlid/Popout Scars, rough irregular depressions where flakes have fallen off from excessive heat.
4.internal Fractures , in translucent material these occur before popouts.
Some examples
Dove of white Vanport with popout scars on shoulder and tip.
Prehistoric doves were not heat treated before knapping in Ohio.

 

[ohiofinds 1]

Vanport flint that has turned black. This was a much greater temperature than the 600 to 750 degrees used to heat treat Vanport before knapping.This Upper Mercer black has popout scars and is more glossy than if it were unheated. Vanport showing internal fractures.These are examples of grey Nellie Chert heated after knapping Here is a gunflint that turned white.
If you have examples and ideas please post them.

 

[Buckleberry]

Nice summation, I would also include:

5.texture, heat treated materials have a waxy feel to them as opposed to smooth and dry.

 

[kansa54]

Heat treating makes most cherts easier to knap. Why would you bother to heat treat something after it has been finished? Are you saying that possibly they were unintentionally exposed to fire?

 

[Tdog]

Heat treating makes most cherts easier to knap. Why would you bother to heat treat something after it has been finished? Are you saying that possibly they were unintentionally exposed to fire?

Good question. I suppose a fire broke out somehow in these cases.

 

[ToddsPoint]

Good tutorial but there is one important point you missed. When you pull a preform out of the kiln (or fire pit) it is not glossy. You only see the gloss after you remove the first flake. Plus, it has to be heated hot enough to form the gloss. It's the same with accidently heated artifacts. They will not show gloss until chipped. Gary

 

[ohiofinds 1]

Right these were heated after they were knapped not to improve workability.
I once tried knapping some overheated vanport that had internal fractures and popout flake scars.
It shattered without any good conoidal flake scars.

 

[dognose]

Interesting results to temperature.

I am confused a little on this. Please clarify.

Did you perform this "heat treatment" experiment? Or, are you exhibiting those with heat treatment in your collection?

I think your statement below is part of my my confusion. You state:
"Artifacts heated after knapping have at least four characteristics."

Yet I think the proper sequence of action would be:
Artifacts knapped after heat treatment have at least four characteristics.

The heat treatment altering the molecular structure of the minerals to align the molecules resulting in a more knapp-able mineral.