Chert biface, Rosalila cache, Copan (CPN P2758) (Artifact 90-1)
By Peabody Museum on Sketchfab
From "Individual Descriptions of Bifaces and Eccentrics" by Payson Sheets. Appendix to Protecting Sacred Space: Rosalila's Eccentric Chert Cache at Copan and Eccentrics among the Classic Maya by Ricardo Agurcia Fasquelle, Payson Sheets, and Karl Andreas Taube (Monograph 2, Precolumbia Mesoweb Press, San Francisco, 2016):
This is one of the finest large chert bifaces of the Maya area. This huge chert biface is notable for its size, thinness, lack of flaking problems such as step or hinge fractures, and the precision in creating its outline. The presumed manufacturing steps began with percussion for early shaping of a thin and large piece of tabular chert. The flaking changed to indirect percussion rather early in the process because of the size and thinness requiring precision in the direction and amount of force and the point of force application. Final finishing was done by pressure flaking. The base is slightly rounded and the tip is pointed. The chert likely came from a source different from the eccentrics and the two smaller bifaces, as it is made from a whitish and slightly more fine-grained material. Flaking details initially were scant in this description because only one side could be examined, and that side was rather heavily coated with organic material, largely green-colored fabric. It also was coated with cinnabar, particularly heavily toward the pointed tip.
Close examination indicated that the biface was covered with multiple layers of organic materials. In some areas the blue-colored cloth was covered with uncolored cloth, in other places the reverse. And another kind of fiber was used for covering, both above and below the blue cloth. It could be agave (maguey) fiber, and it was uncolored. Remnants of twine thread are visible at the basal end. Both basal and distal ends have some possible barkcloth. All three bifaces and nine eccentrics presently are stored with the side with the least incrustations of fiber down, for conservation purposes. The undersides were photographed recently and reveal more manufacturing information than the top sides. Most of the flaking was done by expanding broad fractures, probably by at least two craftspeople. One would operate the punch, presumably of deer antler, while the other or others immobilized the piece to minimize the chances of breaking it by end-shock. Flaking was impressively well controlled, with only two flakes terminating in small hinge fractures. That was followed by careful pressure flaking of the margins to achieve the precise outline. The underside had a considerable amount of red pigment, apparently cinnabar, applied to its more pointed end.
The thinness of the biface relative to its length is extraordinary, and clearly it could only have been manufactured by a highly skilled artisan. The skill exhibited in this piece is equal to the finest of the eccentrics. Because there is no curvature along its longitudinal axis, there is no evidence that it was flaked from a very large percussion macroblade, although that is conceivable. However, it is much more likely that it was made from a chert source morphologically similar or identical to that from which the eccentrics were made (i.e., a laminar chert source). No cortex was detected.
Length 360 mm. Width 96 mm. Thickness 12.2 mm. Weight 517 grams.