Knappability Scale?

[JackCrafty]

I posted this in the "Knapping Floor Tile" thread but I want to start a new thread on knappability.  I get lots of questions on this, so....

On a scale of 0-10 (with 10 being easiest to knap):

10  High-grade Heat-treated

9    Glass/Obsidian

8    True Flint and Highest-grade Cherts

7    High-grade Chert and Medium-grade Heat-treated

6    Medium-grade Chert

5    High-grade Porcelain and Ceramic  (includes high-grade floor tile)

4    Low-grade Heat-treated

3    Low-grade Chert

2    High-grade Quartzite and Rhyolite

1    Low-grade Quartzite and Rhyolite

0    Low-grade Ceramics, Natural Cortex


I usually don't recommend anything lower than a 7 for beginners and for those who want to work on advanced flaking techniques.

[JackCrafty]

The low-grade heat treated (HT) category is kind of difficult for me to define.  I'm going to place both hard and soft materials in this category.

Low-grade HT includes (but not limited to): Keokuk (it cracks way to easily along edges), stone with small heat cracks,  over-cooked stone, and stone that is still hard to run flakes on after heating.

I'm thinking of putting some HT novaculite into this category too but I'm not sure where it comes from.  I've got some white novac that almost feels like soapstone and is very brittle.  Maybe it's over-cooked?

What do you guys think?  I think there are a couple other threads like this and I'll try to link to them...

[Marc St Louis]

I'm surprised you put high grade Quartzite so low Patrick.  The stuff I have worked wasn't to bad to knap and I would put it much higher than 2.

As an aside, there was a Quartz deposit that was found not long ago on a local Ojibwa reserve that clearly shows signs of being used.  I've been trying to find out where it is but have so far been unsuccessful.

[TRACY]

Maybe add some examples of each scale increment. Indiana hornstone and Kentucky blue might fit in the 8-9 scale.

Waldorf has a general scale on ease of knapping in his book on popular stone knappers use.

Good thread!

Tracy

[Outbackbob48]

Patrick, I need to put toilet tank porcelan at the bottom Bob

[nclonghunter]

I thought NC Rhyolite would have been at least a 7...

Good info and interesting

[Zuma]

Here are two examples of what I would rate very high as
far as knap ability.

Heat treated novaculite-- like butter. From Roy Miller.

Porcelain tiles !" thick (from Hudson Bay) trade tower clean up.
like butter too.
I had a few large ones that I never photographed.
Zuma

The ones x out are crapperite. I learned how to not lop
it once in a while bob. lol  a 6 for me

[caveman2533]

How does it compare to Callahans scale?

https://books.google.com/books?id=Wnn3eVROJP4C&pg=PA102&lpg=PA102&dq=Callahan+lithic+scale&source=bl&ots=1cOoH-qnUY&sig=1HtQptobItotWduG9IjDOp7Wx0U&hl=en&sa=X&ved=0CDAQ6AEwA2oVChMIsrPasruUxgIViQOsCh09MgBv#v=onepage&q=Callahan%20lithic%20scale&f=false

[turbo]

I thought NC Rhyolite would have been at least a 7...

Good info and interesting

Haha, well by Callahan's scale it's around 7!

[Chippintuff]

I am glad to see high quality flint/chert rated better than glass and obsidian. Since this matter is affected both by a knapper's tools, experience, techniques and preferences, it is unlikely there will ever be complete agreement on any knappability scale. In my opinion, it's largely a matter of an individual's preferences in difficulties. Though it is an excellent material for learning how to knap to get predictable results, I don't like glass and obsidian's eagerness to pop a flake off. I had rather hit a little harder on a material that is a little more "forgiving". From reading posts by other knappers, it seems that some really like to deal with "tough" materials. Maybe what I am saying is that flakability is not the whole matter, and even "workability" is subject to methods.

WA

[JackCrafty]

Chip, the flakability and workability are hard to define, I agree.  There is wisdom in your post.  The method I'm using is based largely on "frustration level".  I know that's almost impossible to define as well but, basically, if the flake run long AND with good predictability, it's high on the scale.  So, in the case with high quality quartz, I agree that it can be a pleasure to knap, but the flakes do not run "long".

That said, I going to adjust the scale.  I'm downgrading glass and obsidian and upgrading quartzite and high-grade rhyolite.

Caveman, I need to study Callahan's scale tonight.  I'm a little short on time right now.

Zuma, I need to find that "butter tile".  If it's true, someone is going to make some serious $$ selling that stuff to knappers....

[JackCrafty]

Updated Scale:

10  High-grade Heat-treated

9    True Flint and Exceptional-grade Cherts

8    Glass/Obsidian

7    High-grade Chert and Medium-grade Heat-treated

6    Medium-grade Chert

5    High-grade Porcelain and Ceramic

4    High-grade Quartzite and Rhyolite

3    Low-grade Heat-treated

2    Low-grade Chert

1    Low-grade Quartzite and Rhyolite

0    Low-grade Ceramics,  Natural Cortex

[JackCrafty]

Caveman, I took a look at Callahan's scale really quick and I don't agree with it, especially where he places shale and slate.  I'll look at it more closely, along with Waldorf's scale, later...

[Zuma]

Chip, the flakability and workability are hard to define, I agree.  There is wisdom in your post.  The method I'm using is based largely on "frustration level".  I know that's almost impossible to define as well but, basically, if the flake run long AND with good predictability, it's high on the scale.  So, in the case with high quality quartz, I agree that it can be a pleasure to knap, but the flakes do not run "long".

That said, I going to adjust the scale.  I'm downgrading glass and obsidian and upgrading quartzite and high-grade rhyolite.

Now that's almost (phenomenological)

I like your newer chart.
Zuma
PS
I think the thick porcelain tiles must have been installed like cheap marble.
Perhaps for bathrooms and window sills? Just a guess.

[JackCrafty]

Zuma, yes, and quite intersubjectively unstable.