BLADES AND CORES OF OBSIDIAN

The recently opened Ambergris Caye Museum features a number of interesting artifacts from the prehistoric and historic eras on the island. For those interested in the Maya occupation of the caye, a number of items help to shed light on the daily lives of the former residents who were actively involved in the lively canoe trade that flourished here over a thousand years ago. Archaeologists have estimated that the population of Ambergris Caye in 800 A.D. was somewhere between ten and twenty thousand. Over thirty Maya sites have been identified on the island and it is believed that many others are still hidden in the jungle of the island interior.

Some of the more interesting objects left behind by the ancient Maya, and on display at the museum, are the blades and cores of obsidian, a naturally occurring glass produced by volcanic heat and pressure. Obsidian is not found in Belize so the Maya traded for prepared cores from volcanic sources in Guatemala, Mexico and Honduras. Blades were struck from these cores to produce cutting tools of incredible sharpness.

Cores were made from obsidian cobbles found in stream beds adjacent to glass producing volcanoes. Oblong or football shaped cobbles were struck in a way to produce a flat surface at one end. This flat area, or striking platform, was then chipped away along the outer edge using a deer antler and a small hammer stone. The larger blades could then be further reduced by pressure flaking to make projectile points or ornaments. Widely used throughout the western hemisphere and the rest of the world as well) obsidian blades, when freshly struck from the core represent the sharpest cutting edge known, several times sharper than a surgical steel scalpel. In fact obsidian blades are currently in use in some U.S. hospitals for heart bypass surgery. It seems that they cut cleaner, thereby promoting more rapid healing with less scar tissue. Needless to say, obsidian blades constitute a considerable hazard to the unwary archaeologist who chooses to sift through soil in Maya sites with unprotected hands. Even leather gloves are no guarantee against serious cuts.

The first flat blades struck from a core were flat and not particularly useful. Later blades were struck along previous blade scars, producing a blade with a triangular cross-section, something archaeologists call a backed or prismatic blade which has greater strength than a flat blade. It was this prism-like blade that was widely used by the Maya as a cutting tool. Several examples of these blades are on display at the museum.

Eventually the exhausted core would be discarded or, in some cases incorporated into jewel-like body adornments. One such core, found in Mexico, is engraved with the figure of a bird of prey. A royal burial at Lamanai, Belize, contained 571 exhausted cores arranged around the head of the interred individual, suggesting they were part of a head-dress.

Each volcano produces glass with a distinctive chemical composition. Scientists using mass spectrometry have succeeded in identifying the "signature" of many volcanoes known to have been sources of obsidian used in the manufacturing of tools. Almost any blade or core can now be traced to its source. One site on Ambergris Caye produced numerous obsidian blades along with exotic trade goods from all over Central America. X-ray fluorescence and neutron activation revealed the blades had come from three sources in Guatemala., one in Michoacan, Mexico, and the famous green glass variety from Pachuca volcano near Mexico City. The blades and core on display at the Ambergris Caye Museum originated in Guatemala over a thousand years ago.

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