This large chert biface from Mexico is called a tecpatl (knife).  It dates to the Late Postclassic period in Mesoamerican prehistory, ca. 500-800 BP (1200-1521 AD), and was made by an Aztec stoneworker.

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The artefact is curated in the University of New England Museum of Antiquities (UNEMA), MA1994.5.1.

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Bifaces in Aztec cosmology have exceptionally complex symbolic connotations and multiple meanings depending on the context of use and deposition, and bifaces are an important iconographic symbol in Aztec hieroglyphics.  The flint or chert bifacial knife is called a tecpatl in the Nahuatl language (translated as ‘flint’, in contrast to itztli, or ‘obsidian’).  Tecpatl are leaf-shaped in outline, often with pointed ends.  They vary considerably in size and shape, and ritual examples can be more than 60 cm long.  Hafted examples suggest that the narrower end of the biface was considered the handle.  They were sometimes set vertically in temple offerings with the narrower end embedded in resin to hold it upright.  The bifacial percussion flaking is exceptional on many of these examples, and they rank among the most skillfully-produced examples of percussion flaking world-wide.  Tecpatl were made by direct soft hammer percussion, or perhaps indirect percussion with a soft punch, usually followed by non-invasive pressure flaking to regularise the shape and edges.

The tecpatl was used in human sacrifice and, as such, it was a mediator between life and death, the divine and human realms, and earth and the underworld.  Tecpatl used to sacrifice animals and people were special objects called ‘ixquauac’, and these knives were thought to have lives of their own.  A variant of tecpatl was anthropomorphised by affixing stones near the edge on one face to represent an eye and teeth, creating a face in profile.  These tecpatl are thought to be symbolically linked with the underworld, and many examples have been found in excavations at the Templo Mayor in Mexico City.

A cache of 27 white chert tecpatl, and one brown example, were excavated at the Templo Mayor in 2013.  They may have personified warriors or minor deities rather than human sacrifice.  The tecpatl glyph is carved onto the tongue of the central deity in the Aztec Sunstone, Tonatiuh (the Aztec sun deity) and the glyph also occurs in the first ring of the stone, representing Day 18 of the 20-day month. Tecpatl is also the symbol for the third quarter in the calendar round.  The glyph represents the north cardinal point, the direction of death and cold.  The Aztec observed that chert can make sparks (either through striking pyrite or through triboluminescence), symbolising starlight on earth, and some researchers have interpreted the dots and tecpatl-like glyphs on the edge of the sun stone to represent a starry night sky.  Smaller tecpatl were given handles, such as the famous ‘eagle warrior’ knife in the British Museum.