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

usually associated with the reduction of microcrystalline-quartz materials, were employed
in the production of the majority of obsidian eccentrics. Bifacial reduction by pressure is
not closely tied to the successful manufacture of Classic Maya prismatic-blades. Whether
flint-knappers were made to produce obsidian eccentrics, or if obsidian workers gained
new technological knowledge of bifacial reduction is unknown. In either case, however,
the obsidian craft specialists of the Yaxche phase had to compromise with new
ceremonial and political demands. In addition to the old symbolic forms, new ones also
were introduced (Figure 7.21), indicating that both symbolic and technological shifts had
occurred in how cache materials were meant to be produced.
Table 7.6 illustrates technological changes through time in obsidian eccentrics at
Piedras Negras. The dominant technique for creating obsidian eccentrics during the
Balche and Yaxche phases was to notch blades and flakes, and to a lesser extent,
exhausted cores. The number of notched cores increased with the transition to the
Chacalhaaz phase. The major shift, however, occurred during the early Chacalhaaz
subphase where the number of bifacially-worked obsidians overshadowed other forms.
After the early Chacalhaaz phase, and the decline of the dynastic line at Piedras Negras
marked by the defeat of Ruler 7 by Yaxchilan, notched-flake eccentrics once again
become the norm (Figure 7.22). However, these flaked eccentrics do not adhere to the
system established during the Yaxche phase. Many of the same symbolic forms are
retained during the Chacalhaaz phase (Figure 7.16), however, they are made with
different techniques. Thus, Terminal Classic obsidian eccentrics can be best characterized
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