Neutron activation
Obsidian, a volcanic glass, comes from several geological sources in Mesoamerica, as listed above. Each of these sources has a distinctive “fingerprint” of trace elements that proportionally vary due to the individual circumstances of each source's formation. Neutron activation analysis (NAA) and X-ray fluorescence (XRF) are two analytical methods used to identify the types and amounts of trace elements. These data are then statistically compared to data already available for the known sources.