Obsidian or Absurdium ?

[kootenay joe]

Here are 2 knives both said to have hand knapped obsidian blades. The smaller one was a B.I.N. for $20. The blade is described as "smokey clear obsidian knapped by Kenny Hull who is "one of top 10FOG knappers in the world".
In hand this knife is very light weight and the blade is transparent, i.e. beyond translucent, i can look through the blade and read writing on paper beneath it. However looking on line i can find no description of obsidian that is anything other than opaque and usually black.
So is this really hand knapped obsidian ? or is it glass or acrylic poured into a mold ?
I messaged the seller and politely asked what the blade is made of and received this reply:
"The blade is obsidian Knapped by kenny Hull. He is a very talented Knapper and his work has been collected around the world for more than 20 years. Thank you for asking."
Here are some pictures. I know nothing about obsidian and my hope is that someone here has experience with this glassy rock.
The other 'obsidian' knife i will present in a later post in this thread.
kj

[RalphAlsip]

My opinion is that it is "as advertised". My guess is that it would be very sharp and would make a very ragged cut. It would likely be brittle which means it would break / chip if used to pry or if it were dropped on a hard surface.

It looks like very good workmanship and was probably knapped with modern tools rather than the way the craftsmen from 5,000 plus years ago did it.

[Berryb]

I used to do a lot of obsidian knapping back in my youth. Most of the stuff we used came from Glass Butte near Burns Oregon. I often had pieces that were that clear. There was other stuff that was more opaque black often with red shot through it. It was easier to work, not quite so fragile.
Bruce

[kootenay joe]

Thank you gents. Now i wonder why sell these for $20 ? There must be some time consuming work to do the knapping and then to rawhide it into an antler tine, plus cost of materials. For value here this is then is the 'Rough Rider' of obsidian knives.
His web page says to not use this to cut food. Why ?
kj

[orvet]

His web page says to not use this to cut food. Why ?
kj

Because obsidian can chip and it is essentially volcanic glass. Using it to cut food could result in you ingesting glass chips.

My grandfather was an am amateur archeologist in the 1950s who found thousands of obsidian artifacts in the Willamette Valley not too far overland from Class Butte Bruce mentioned.
Grandpa figured out how the natives chipped arrowheads using native tools. He used antler to flake the obsidian. I have seen him make a perfect artowhead in about 5 minutes. It was surprisingly simply! It really had to be because you find these obsidian artifacts all over the North West by the thousands. There are trading sites where the Indians traded for obsidian and places where they sat and chipped arrowheads and other tools.

[kootenay joe]

Thanks Dale. I had not thought of it but a sharp chip from the obsidian edge could make some nasty cuts in your GI tract, mouth to 'exit'.
Here is my other 'obsidian' knife, a big 11 3/4" that is heavy, 13 ounces or 371 g. The edge is not sharp and if i place a small magnet on a wood surface and hold this blade about 1" above it, the magnet jumps up and sticks firmly to this blade. As best as i can find out obsidian is not magnetic.. Could this blade have been made by pouring melted metal into a mold ?
kj

[Berryb]

Doesn't look like obsidian to me, but flint or chert. Much more difficult to work but also much more durable. It can be made quite sharp but it takes time and skill that few modern flint knappers have, especially with primitive tools like antler. Obsidian will flake to a mono-molecular edge if done properly, that is seriously sharp but not too stable.
Bruce

[kootenay joe]

Thank you Bruce. I just looked up 'chert' and it does look like this blade. I also learned that "Chert is a microcrystalline or cryptocrystalline sedimentary rock material composed of silicon dioxide (SiO2)". So, very different from obsidian which is of volcanic origin.
Chert can have a reddish hue if iron oxide is present. This blade has no reddish hue anywhere yet is strongly attracted to a magnet. Nowhere did i read that chert is magnetic. Does this mean the blade cannot be chert ?
kj

[danno50]

I personally know a half dozen modern flintknappers (all of them either professional or amateur archaeologists) who work extensively with local cherts and flints. However, their most preferred materials are obsidian and knife river flint, which is a high quality brown chalcedony which mostly comes from North Dakota. A friend of mine bowhunts with arrow heads he knapped himself from knife river flint.
Archaeologists and geologists use different criteria to classify lithic materials. If you start looking through a guide to rocks and minerals it can get very confusing. Flints, cherts, chalcedonies, obsidian, quartz and quartzite (the most common lithic materials used for tool stone) are all primarily composed of SiO2. The most common element in the earth's crust, by weight, is oxygen, due to the vast amount of rock made up of primarily SiO2. Most lithic materials used by the early natives for tool manufacture were heat treated in some fashion, prior to using, to improve the flaking qualities.
There was a trade network across the great plains in prehistoric times. Here in Saskatchewan, we find some artifacts made from obsidian and also find many artifacts made from knife river flint. Both materials which do not occur locally.
There was an archaeologist in the US, by the name of Don Crabtree, who came down with cancer and needed surgery. He found a surgeon who agreed to use surgical instruments manufactured by himself by knapping. Not sure if the material he used was obsidian or flint?
Roland, very puzzling as to why the blade of the second knife you posted should be magnetic?
The disclaimer not to use the obsidian knife for food preparation is probably for liability reasons? People using a knife of this type, in a modern kitchen, may be prone to cutting on too hard a surface resulting in small chips getting into the food? In prehistoric times all food preparation was done with stone tools.
Dan

[kootenay joe]

Thank you Dan. A very interesting post.
The big blade is strongly magnetic so i think it has to have a lot of iron in it, like steel.
A quick search finds that " iron, nickel, cobalt and some alloys of rare earth metals" can all be magnetized. Hence this blade must be made up largely by one or more of these metals.
If there could be any other possibilities please post it.
kj

[Dinadan]

Joe - if that knife attracts a magnet that strongly then I bet it is a fake stone. I have seen those kind of pretend stone knives for sale. Try taking a small file and see if you get shiny steel when you make a pass.

[Berryb]

Sort of related; I met Don Crabtree and Francois Bordes at a workshop at WSU in Pullman in the early 70s. At the time they were the two best flint knappers in the world. Crabtree had recently figured out how to make long thin Meso-American blades with a chest punch. Up to then It was a technology that had died with the Aztecs. Bordes was a French university Professor. Other than his skill what I remember about him is he swore in English. His French students didn't know what he was saying, but we did. All in all an interesting weekend, Thanks for helping me recall it.
Bruce

[danno50]

Bruce, great that you had the opportunity to meet one of the old timers like Crabtree. The chest punch is also one theory on how the Folsom people made the deep flutes on their points. There is a young grad student at the university here who came up with a simple lever/fulcrum type device with which he can produce reproduction Folsom points with amazing flutes. He showed it to me quite a while ago and I cannot remember well enough to describe it any better than that. Sorry, last derailing digression from me in this thread.
Dan

[kootenay joe]

No derailing here at all. In fact it is the digressions that add interest and often useful information & thus enrich the threads.
kj

[bighomer]

KJ is absolutely correct I've enjoyed each and every post, I've learned something. good stuff, thanks

[Colonel26]

I love this stuff. Great information guys.

[orvet]

Roland,
That point of yours does not look like any obsidian I have ever seen. I have never seen magnetic obsidian, at least not here in Oregon. I’m not sure there is such a thing but I’m no expert.

The edge on yours does not look like obsidian to me. It looks different than any obsidian I have ever seen. I don’t have any good examples of arrowheads but I happened to remember some broken chips of obsidian points I run across the other day in my shop. These are little pieces of arrowheads that someone has found.

The picture is lousy, at 4 AM I’m not going to set up a perfect environment to shoot a picture, but I think you can see that the edge of obsidian is rather jagged and can be extremely thin. There is at least one piece here that is translucent enough that you can see through the edge.

I should have put something in the picture for scale. Suffice it to say all those chips will sit on a Quarter.

Someone mentioned using obsidian in surgery, because of the incredibly fine sharp edge that is achievable with obsidian I understand it has been used in microsurgery. I think the article I read said they use it in some sort of surgery around the eye. Maybe it was a cornea transplant, I can’t remember now, but they do use it surgically because it gets so incredibly sharp and the edge can be very thin.

[CheckSix]

A long time ago, I majored in Geology. I've forgotten a lot though. I Googled magnetic properties of Chert and came up with this...
Apparently, some regions of this mineral have magnetic properties...
http://journal.frontiersin.org/article/ ... 00035/full

[kootenay joe]

Dave there is no mention of strength of magnetism that can be found in chert. I think they are using devices that detect very low levels of magnetism and the degree of magnetism is too low for a magnet to adhere. Do you think this is a correct reading of the article ?
kj

[CheckSix]

My point was, If there is enough magnetite or hematite in the chert/flint, it may be enough for a magnet to be attracted to. This is my idea to explain the knapped blade you have.

[kootenay joe]

Yes, i do understand that, but this blade is strongly magnetic, able to get a small magnet to jump up 1-2" to stick to it.
My question is: could chert contain enough magnetite or hematite to be this magnetic and still be a chert ? Or: do trace amounts of these 2 substances cause an intense magnetism ?
I just tried filing the edge as suggested in an earlier post. The blade is extremely hard. After a few minutes of filing one small area, i have exposed a tiny spot of shiny appearance. If metal it is: heavy, hard & strongly magnetic.
What i now realize is that regardless of blade composition this is a real dagger with lethal ability. The edges are about as sharp as a regular dagger, i.e. not shaving sharp, it is the pointy tip that gives a dagger the ability to puncture & penetrate. Shaving sharp edges are not needed for it's function and are difficult to obtain given the blade geometry.
Knowing that it is better than just a 'tourist item' class of knife helps me accept it, even without knowing what the blade is made of.
kj

[CheckSix]

Your knapped blade that attracts a magnet, may have just enough Iron in it, for this to happen. Try the other way around, take a steel bottle cap for example, that the magnet will pick up and see if your knapped blade will do the same. If it doesn't, then it is just high enough in Iron content, for the magnet to be attracted to it.

[kootenay joe]

I'm away from my knives for a few days but when i get back i will do the experiment as you suggest and post the results (~ 5 days).
kj

[terryl308]

kJ, could your knapped point be made out of meteorite? Can't believe anyone would use it because of the cost but I believe it is magnetic. Terry

[Dinadan]

Since it attracts a magnet quite strongly I still think it is most like a steel knife made to look like stone. Here is an example of one from Sage Blades. Not quite as convincing as Joe's knife since it has bee sharpened.