Wednesday, May 29, 2013

Why a Blade Core is not like an Artichoke

Microblades and core
Recently a friend who was teaching an introductory archaeology class commented on a  testbank question for the course textbook that described blade making as "similar to peeling long leaves off an artichoke".  Blades are long linear stone flakes with parallel edges that have been systematically removed from a prepared core.  Artichokes are an edible thistle.  Making blades and peeling leaves are really quite different, although in an effort to find common ground, I will acknowledge that when viewed top down, the pattern of blades in a completely reconstructed blade core and the overlapping leaves in an unprocessed artichoke (with its top cut off) do resemble each other.

Artichokes have overlapping leaves
My friend pointed out that the average undergraduate student has probably never processed a whole artichoke and therefore are not going to be intimately familiar with their internal structure and leaf pattern.  Which is probably enough of a reason to discard the question on its own.  An analogy works better if one of the things being compared is familiar.

Looking down onto the platforms of a core with six refit
microblades.  The numbers are the sequence in which the
blades were removed.  I would probably take the next blade
 off in the lighter coloured corner behind blade number 4.  
As a flintknapper, my biggest problem with the comparison, especially in an archaeology class, is that it completely removes the input of human beings from the blade making process.  Our brains and hands are a crucial part of the process.  Pulling the leaves off an artichoke is easy.  The leaves are already clearly separated and all it takes to remove them are fingers, lips, teeth or a beak with enough clamping power to grab one and pull it off.  Striking long, parallel sided blades from a homogeneous core of stone is a completely different story.  The blades are not neatly stacked within a piece of flint or chert.  There are no internal seams or natural fractures that create the blades.  The entire process from beginning to end is controlled by the knapper, who must first visualize the blades and then carefully and systematically set-up the stone core to begin removing them.  Every blade removal is individually planned and prepared and its success or failure depends on the preparation and skill of the knapper and will, in turn, influence the progress of the whole operation.  The knapper must continually adapt, plan, chip and grind the core for each successive blade removal.  An ostrich could peel an artichoke and end up with the same pile of leaves that a monkey or Sous-chef could make, but it takes years of training and practice to make a consistent series of blades from a lump of stone.

Here are the same six microblades laid out in the sequence in which they came off.  Numbers 1 and 2 have pronounced curves and lots of scarring on their dorsal surface from when I pressure flaked the first ridge for the blades to follow.  Number 3 and 4 continue to clean up the core and established new ridges for the next blades to follow.  Microblades 5 and 6 are long linear flakes with well defined arrises (the central ridges that the blades follow along).  You can see the scar left on the core from removing blade number 6 - the last in the sequence.  There is still lots of rock left, probably enough for another 15 or 20 blades if everything went well.

Obviously it looks more like a
 tulip than an artichoke OR a
If I was forced to make a vegetable analogy for blade making, I think I might go with cutting french fries from a potato one fry at a time, if you tried to make all your fries with triangular or trapezoidal cross-sections and you used a knife that produced a slice that was 130 degrees off the angle that you applied pressure to it and the potato was as brittle as if it had been frozen in nitrogen and the french fries were 2 mm thick and razor sharp and once you started slicing a fry the whole cut was finished in a fraction of a second and you had no opportunity to re-adjust whether the cut was going in the direction you wanted or not and if a lifetime of exposure to french fries caused irreversible lung damage and no one really ate french fries anymore because something better came along a few thousand years ago.

Or maybe, preparing vegetables isn't very much like knapping at all.

Photo Credits:
1,3-5: Tim Rast
2: Wikipedia:


  1. Replies
    1. Yes - the stone used to make the microblades in this post is Mook Jasper or Mookaite from Australia. Its very nice to work. I picked up a chunk at Green's Rock and Lapidary in Calgary a year or two ago.


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