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

kilometer radius of the site center. The ubiquity of cortical nodule reduction flakes and
nodule fragments, however, indicates that the source was nearby. The lack of river-worn
cortex suggests that the source may have been located inland, away from watercourses. It
can be characterized as translucent white to blue in color, but it develops an opaque white
patina through time. It is very difficult to work, and the quality is largely heterogeneous.
Heat treatment processes can explain variability in the color and quality of both the
chalcedony and chert. However, evidence to prove the systematic use of this technology
has not yet been compiled.
Other local materials consist of pebbles and cobbles washed out from arroyos and
the Usumacinta River itself. These materials can be described as chalcedonies, jaspers,
and other sedimentary and metamorphic rocks that produce a conchoidal fracture pattern.
The colors are quite diverse and can range from bright red to green. Water-washed or –
rolled materials do not seem to have been commonly reduced at the site, but can be
identified by remnant river-worn cortex. They were used sparingly for flake cores and
small bifaces at Piedras Negras, but seem to be much more common at the secondary
sites of El Cayo (Lee and Hayden 1989) and Macabilero (Golden et al. 2004).
Macabilero, in particular, seems to have had extensive biface and flake-core industries
using creek-worn cobbles.
4.1.2: Imported Microcrystalline Quartzes
Materials that likely were imported from outside the region consist of fine grey,
fine pink, and fine brown, and extremely coarse-grained microcrystalline quartzes. Some
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