The actual volume or weight of obsidian at Qillqatani is relatively small. Obsidian from the Chivay source appears in small quantities in nearly every stratum in the approximately 8000 year sequence. The most informative data on long distance exchange come not from the total mass of obsidian, but from the variability in the relative percentage of obsidian flaked and obsidian tools in each lithic assemblage through the sequence. Nevertheless, the weight of obsidian tools at Qillqatani totals 43 g, and the sum of the weight of obsidian flakes is 382 g out of a total of 11,085 g of lithic material. Thus, the entire quantity of obsidian excavated at Qillqatani is only about 1.5% of the cargo that could be carried by a single llama.

These figures are meant to highlight a central issue with obsidian studies overall: the actual quantities of obsidian encountered and evaluated from the consumption sites throughout the south-central Andes are relatively low. The significance of obsidian circulation over the larger region is not matter of weight or volume, but rather a question of consistency and changes in the proportions of particular sources utilized over time. These data from Qillqatani underscore this issue. A comparison of the persistence of non-local obsidian at Qillqatani as of level 24 (X

Table 3-6XandXTable 3-7X) with the non-local obsidian at Asana (XTable 3-4X) during earlier periods of the Archaic, suggests that on a regional scale mechanisms of exchange, or direct acquisition, were more intermittent during the earlier Asana phases. In contrast, Qillqatani has high quality cherts and low quality Aconcahua type obsidian available in the immediate proximity of the rock shelter. Thus, the question becomes: why transport Chivay obsidian 200 km when alternative materials are locally available? Further, why was the transmission of Chivay obsidian so consistent through time? In this perspective the low but consistent quantities of Chivay obsidian that were conveyed throughout the south-central Andean highlands during the prehispanic period can be seen as a gauge of highland interaction and horizontal complementarity, with wider implications for exchange.