A CAST of a precolumbian blade core. In 2012, Occpaleo was able to acquire this example of an obsidian blade core from Pre-Columbian Mexico for molding and casting. It is 6 and 3/8th inches long, and shows the prismatic blade scars of the finest precision core work known in history. The black opaque obsidian in this blade core is consistent with the variety used in the Ucareo Obsidian Mines of Central Mexico during the Classic to Post Classic around 500 to 1,000 AD. These mines were used to supply such sites as Tula and Chitzen Itza (Healan 1997), and this example compared well with examined cores in the collections of the Smithsonian Institution from Central Mexico of sites in the region.
Archaeological evidence has shown that these core were made with a unique method of hardwood rods and pegs and a "pry" method. The blades produced are so precise, that they can be used for scalpel blades that are sharper than surgical steel blades when viewed under a microscope. Fracturing down to a molecular edge, they cut skin instantly on contact without pressure. These blades were also inserted into the famous Aztec war clubs to make the Macuahuitl, or "Obsidian Sword" which was very feared in the Spanish conquest accounts. (ex Alan Brown coll., ex. Gilbert Cooper coll.)