Chert biface, Rosalila cache, Copan (Artifact 90-6) (CPN P2711)
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 two smaller chert bifaces, much smaller than Artifact 90-1, the large biface. This biface is 160 mm long, 49 mm wide, and 10.9 mm thick. It weighs 87 grams. Both this one and the other smaller one (Artifact 90-2) were manufactured in similar fashion and were likely made by the same person, the apprentice. And these two smaller bifaces show the same style of manufacture and level of expertise as the three eccentrics, Artifacts 90-3, 90-4, and 90-9. Both smaller bifaces exhibit a quite high level of skill in manufacture, with only very slight manufacturing errors in the form of hinge or step fractures. The lack of curvature along the longitudinal axis indicates this probably was not made from a large percussion blade from a large core. Rather, it probably was made from a piece of laminar chert from the same yet-to-be discovered source as the other small chert biface and all the eccentrics from this cache. Virtually all the flaking visible on both faces probably was achieved by indirect percussion (i.e., using a punch) and effectively stabilizing the biface to avoid end shock. A small facet was left toward the base. This and the other smaller biface lack the careful and precise pressure flaking that was performed on the larger one (Artifact 90-1). The two smaller bifaces were pressure-flaked as the last manufacturing step, and the precision of that final work is not quite as good as that on the three rougher eccentrics. The result is a slightly more irregular edge in outline and in edge-in view, in clear contrast to the precision of an exceptionally acute and sharp feather edge as achieved on the large biface.
The biface has a 14 mm-long basal facet, similar to the basal facets on many of the eccentrics. The base up to about 45 mm on the blade surface has considerable amounts of cinnabar coloring on both faces. It also has some blue and green pigment applied to it.