Focus on finds – pumice

Three examples of pumice found at the Ness of Brodgar. (Sigurd Towrie)

Three examples of pumice found at the Ness of Brodgar. (Sigurd Towrie)

Pumice.While it may not be the most glamorous of finds from the Ness, that pumice played a role in Neolithic life is beyond doubt.

A by-product of volcanic eruption, pumice is hard, rough-textured, vesicular (very small bubbles) and floats. It is found on the beaches of the Western Isles of Scotland and Orkney and Shetland.

It has floated to its destinations, disgorged by volcanic eruptions in Iceland and may have been at sea for many years, before washing ashore.

Pumice is found on archaeological sites in Scotland (and many other places where volcanic action sends it), and clearly was being used, as you can see from the photographs here of a selection of the pumice found at the Ness of Brodgar.

Pumice.These days pumice scrapes dead skin off feet and elbows; it distresses denim, when fashion demands it be stone-washed; is used to filter water; to make light-weight concrete and put the abrasive in toothpaste, soaps and hand cleansers.

The pumice excavated archaeologically was collected from the shore and taken back to settlements for its same abrasive qualities, and the grooves and angled faces we find on the Ness pumice are the most obvious clue to think through what it was being used for.

Suggestions made by specialists Ann Clarke and Andrea N. Smith include its use on wood, whale and other bone (e.g. bone pins), working skins, burnishing pottery and refining the spatulate tools of the Ness. 

Pumice.Experimental work on pumice has not been carried out and we need to think too about uses which don’t leave a trace on the surface of the pumice or that what we find is yet to be processed for future use, for example crushed and added to fat to make an abrasive mixture.

Whatever pumice was collected up to be used for, it is another element of how people of the past made use of their immediate environment and what it produced.

Its presence at the Ness, at any other site across the millennia in Orkney, allows us further insight into what folk did and how they did it.

Pumice.Archaeologists take pause over all that we find on a site, asking why it was collected, and exploring all that time (and funding) allow us to explore.

And as a footnote, pumice must not be confused with scoria, which also appears in Orkney, which doesn’t float, and probably therefore is a product of the much more ancient volcanic processes of Orkney’s own geological past.

Further reading

  • Working Stone – pumice
  • Ann Clarke (2005) The Pumice from Barnhouse. In Richards, C. Dwelling among the monuments. McDonald Institute Monograph
  • Andrea N. Smith (2007) Pumice. In Hunter, J. Excavations at Pool, Sanday . The Orcadian Ltd.

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