Prismatic blade

[3] Prismatic blades were used for cutting and scraping, and have been reshaped into other tool types, such as projectile points and awls.

The ventral surface of the prismatic blade is very smooth, sometimes bearing slight rippling reflecting the direction of applied force and a very small bulb of applied force (indicative of pressure reduction).

The dorsal surface, on the other hand, exhibits scar ridges running parallel to the long axis of the blade.

Obsidian prismatic blade production was ubiquitous in Mesoamerica, and these tools can be found at a large majority of Mesoamerican archaeological sites from the Preclassic period on until the arrival of the Spanish in the early 16th century.

Fray Motolinia, a Spanish observer, recorded: 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.