The Organization of Chipped-Stone Economies at Piedras Negras ...

Percussion-prepared cores were further reduced by percussion at Piedras Negras
to regularize the facets of the core for pressure-blade production. Obsidian eccentrics and
other obsidian artifacts indicate that the initial reduction of imported cores was
systematic, and that particular kinds of early percussion flakes and blades had specific
functions in the reduction of polyhedral cores from El Chayal (described below).
Obsidian workers at Piedras Negras preferred a rounded working face and a lack of
original percussion scars (i.e., remaining percussion scars from initial core production
elsewhere, probably at the El Chayal source) before they began the blade-making
process.
Small percussion flakes and blades (Figure 6.3) were removed to regularize the
face of the core. They represent removal of undulations, cortex, and hinge terminations
that remained on the face of the imported core from its initial production at the El Chayal
source (Figure 6.4). When possible, blades were removed to create straight facets
extending from the platform to the distal end of the core. If the blade stopped short or
ended in a hinge termination before the detaching fracture reached the distal end of the
core, knappers at Piedras Negras removed distal flakes and blades to complete the
regularization. However, early distal rejuvenation blades (Figure 6.3) appear to have been
removed as a basic regularization technique that created long, smooth facets prior to
pressure reduction. Most distal rejuvenation blades and flakes were not part of the two-
step process outlined by Clark and Bryant (1997:116), wherein a flake was removed from
the distal end of the core to create a platform for distal rejuvenation blades taken from the
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