River patina on flint artifacts: Features and genesis

The intensely brilliant luster present on artifacts that were long subjecte d to waterflow is herein referred to as river patina. This condition is fre quently attributed to water flow tumbling of the artifact and abrasion resu lting from the movement of water-borne materials. Although abrasion is a co ntributing factor its contribution to the artifact's remarkable brilliance is indirect.,It is suggested that chemical dissolution of the artifact's su rface is more directly responsible. Dissolution processes remain active whe n natural precipitation maintains water silica content below saturation lev els. The possible presence of a submicron layer of amorphous silica gel on the dissolving surface may be an additional factor in the brilliance of aff ected artifacts.