Obsidian Use in Mesoamerica - Production Techniques

Production Techniques

Due to its cryptocrystalline internal structure, obsidian is relatively easy to work, as it breaks in very predictable and controlled ways via conchoidal fracturing. This contributed to its prolific use throughout Mesoamerica. It is obtained by either quarrying source sites or in nodule form from riverbeds or fractured outcrops.

Following the removal of cortex (when applicable), bifacial, unifacial, and expedient flake stone tools could be produced through lithic reduction. The use of pecking, grinding, and carving techniques may also be employed to produce figurines, jewelry, eccentrics, or other types of objects. Prismatic blade production, a technique employing a pressure flaking-like technique that removed blades from a polyhedral core, was ubiquitous throughout Mesoamerica.

Modern attempts to redesign production techniques are heavily based on Spanish records and accounts of witnessed obsidian knapping. Motolinia, a 16th century Spanish observer, left this account of primatic blade production:

It is in this manner: First they get out a knife stone (obsidian core) which is black like jet and 20 cm or slightly less in length, and they make it cylindrical and as thick as the calf of the leg, and they place the stone between the feet, and with a stick apply force to the edges of the stone, and at every push they give a little knife springs off with its edges like those of a razor."

As the distribution of obsidian sources in Mesoamerica is generally limited, many areas and sites lacked a local obsidian source or direct access to one. As a result, tool curation through edge-rejuvenation and/or resharpening was commonly used on larger-mass tools, such as bifaces, to prolong the tool’s (and the raw material’s) utility. While prismatic blades were generally not curated (in the traditional sense) due to their small size, utility of the tools may have been maintained by changing their function. In other words, as the edge of a blade lost its sharpness after long-term use, the blade may have been used in scraping activities, which does not require a very sharp edge, than as a cutting implement. Other curation techniques of prismatic blades involve reshaping them into other tool types, such as projectile points and awls, for example.