Identifying grinding, scoring and rubbing use-wear on experimental ochre pieces

Ochre pieces were used experimentally for a variety of grinding, scoring and rubbing activities to record and compare the use-wear markings that each activity creates on the ochre piece. Ochre that is ground on coarse or fine-grained slabs develops parallel striations that cover the surface of the piece. The striations have unfrayed ends. Grinding is the only activity that results in significant changes to the surface shape of the ochre, producing a plane. When ochre is scored either to create a deliberate design or to produce powder, the grooves that form often do not reach all the edges of the used surface and they regularly have frayed terminations. This demonstrates that the incisions were created by multiple scoring strokes. When ochre is scored to manufacture ochre powder the incisions that are generated are parallel groups of grooves with erratically oriented grooves as well. Bone and wooden tools are soft and they therefore do not generally create obvious incisions on ochre pieces. Grooves created through grinding on a slab or scoring with a stone tool have microstriations within them and they show a range of profile shapes. The most common use-wear from rubbing ochre on animal hide, human skin, human hair and wood is smoothing, edge rounding and polish, although incisions and microstriations also occur occasionally. Residues are often left on an ochre piece after rubbing or scoring with organic materials. The comparative collection of macro- and microscopic use-wear marks from experimentally ground, scored and rubbed ochre is useful as an aid to classifying archaeological collections of ochre. (C) 2010 Elsevier Ltd. All rights reserved.