Red Hill is, perhaps, one of the most petrologically unique obsidians in the Southwest.
Nodule densities are very low, usually less than 5 per 25 m 2 . The largest nodule recovered was 8 cm in diameter, but most of nodules were 5 cm or less. Cortical material varies from a thin gray or brown to glassy. The knapping quality is excellent, equal to any in the Southwest. Bipolar reduction stations and isolated flakes commonly occur, but in very low densities commensurate with the low geologic density.