This flake of high-quality flint eroded from a coastal Aboriginal site in South Australia onto a modern low-energy cobble beach. The edges were retouched by rolling among the cobbles, retouching the edges and exposing unpatinated black flint.
Natural damage like this is referred to as ‘taphonomic’ damage by archaeologists. Most of the taphonomic retouch is unifacial, towards the dorsal surface of the flake, but some damage occurred to the ventral surface. The earlier flake scars, and the ventral surface of the flake, show a bluish-white patina similar to that often seen on highly siliceous stones like chalcedony. This contrasts with the white outer cortex of the flint nodule. The natural retouching scars are black and unpatinated.