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

typological variation also may stem from this framework, but tighter chronological
control between sites is required.
5.4: TOOL TYPES AT PIEDRAS NEGRAS
In the following section I describe the tool types found at Piedras Negras. Types
not found at Piedras Negras are drawn in black outline (Figure 5.2), but they are not
described in detail, because they are thoroughly described in their own site reports (see
Table 5.1). Materials and basic technological descriptions are included to emphasize the
local character of Piedras Negras tool assemblages. I begin with a description of the
microcrystalline quartzes found at Piedras Negras, including local and nonlocal stones.
5.4.1: Morphological and Technological Description of Tool Types
A variety of tool forms are were made of microcrystalline quartzes. The other
chipped-stone material most commonly used at Piedras Negras, obsidian, was worked in
much more predictable ways because of the limited number of techniques used to reduce
it. Polyhedral cores reduced by pressure represent the majority of obsidian artifacts found
at the site. Bipolar reduction was the only other technology used on obsidian, but it was
reserved for percussion blades and exhausted cores to make obsidian eccentrics 16 , and
rarely for platform rejuvenation (see Chapter 6). Pressure flaking was also used to make
the final eccentric forms.
In contrast, the major microcrystalline-quartz bifaces and unifaces used at Piedras
Negras were created with a wider variety of technologies and reduction techniques than
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