This category encompasses the types of stone, and types of use, that are not covered within the previous categories. The evidence is dominated by Late Neolithic Orcadian finds.
Used piece of pumice from Skara Brae ©NMS
Painted slab discovered in Structure Eight under excavation at the Ness of Brodgar ©ORCA
There is evidence, from the Northern and Western Isles (e.g. at Skara Brae, the Links of Noltland and Ness of Brodgar on Orkney, at Eilean Domhnuill, Loch Olabhat, North Uist and at Northton, Harris), that pumice (produced by volcanic eruptions probably in Iceland and washed ashore in Orkney and the Western Isles) was collected from the shore and used as an abrasive (e.g. for smoothing and sharpening bone objects, such as the large fine pins as found at Skara Brae ) during the Neolithic.
It has not been found on sites lying over 10 km from the coast, however, suggesting that its use was opportunistic rather than systematic. The pumice is datable to specific eruptions by means of the tephra it contains; Peter Ditchfield, at the Oxford Laboratory for Art and Archaeology, is currently researching this matter, and samples from Northton have been taken for this purpose.
left: Ochre grinders, Skara Brae ©NMS
right: Haematite, Skara Brae ©NMS
Ochre (hydrated iron oxide, limonite) was used as a colourant in Late Neolithic Orkney – where it is readily found as a loose, earthy stone – and the spectacular recent discovery of painted stones at Ness of Brodgar demonstrate one of the uses of this substance, which produces yellow and brown colours. Small containers of stone, whalebone, fired clay and limpet shell, used for grinding small spherical lumps of ochre (which must have been mixed with some kind of binder, possibly fish oil or blubber), are known for example from Skara Brae , where Childe described them as 'paint pots'.
Haematite (the mineral form of iron oxide) is also known to have been used in Late Neolithic Orkney, with lumps and traces being found, for example, at Skara Brae and Crossiecrown and, most spectacularly, as painted pigment on stones at Ness of Brodgar.
Whalebone 'paint pot' for ochre ©NMS
This mineral, which occurs as solid nodular lumps, probably had two functions: firstly, as a producer of red and red-brown pigment (as indicated by the Ness of Brodgar painted stones, and demonstrated experimentally by Arlene Isbister (Isbister 2000)); and secondly, as a polisher for hides (although this function has not been demonstrated, and the many cattle astragaloi found with rub-wear at Orcadian Late Neolithic sites may have additionally, or alternatively, served that purpose). Haematite could have been used in two ways to create pigment: it could have been powdered and mixed with water (as seems to have been the case, for example, with the whalebone 'paint pot' from Skara Brae).
Alternatively, Isbister's experimental work has shown that the distinctive facets seen on many lumps of haematite could have been produced by pulling a nodule along a carved groove, to fill the groove with pigment. That other substances in addition to ochre and haematite had been used in Late Neolithic Orkney to produce pigments is suggested by George Petrie's observations of finding masses of red and white pigments at Skara Brae, along with 'a small piece of red pigment, which had apparently been partially rubbed down' (Petrie 1867, 210).
The other stones included in this section come under the heading of 'mystery items', whose function is uncertain, and comprise: i) a star-shaped plaque of shale or shale-like stone from Skara Brae, which could have been used as a kind of bobbin, for storing or winding cord; a similar object is known from Taversoe Tuick, Rousay and ii) a sizeable slab of sandy flagstone with a deliberately crenellated upper edge , again from Skara Brae (with a parallel from Ness of Brodgar ).
Crenellated flagstone, Skara Brae ©NMS
There is an echo, in the design of these stones, of the devices used in the recent past elsewhere in the world for scutching flax, although in the absence of evidence for flax cultivation in Late Neolithic Orkney (although evidence does exisst elsewhere in the UK, including Balbridie, Aberdeenshire) , this cannot be put forward as a strong suggestion. In theory these slabs could have been used for threshing cereals, but other uses are possible, and indeed these need not have been utilitarian objects. (cf. some of the 'special stone objects' described above, which may have had a utilitarian function.)
Star shaped plaque of shale or shale like stone, Skara Brae. ©NMS
The research questions surrounding all the stone covered in this section are as follows:
- •Is the use of colouring agents in Neolithic Scotland limited to Late Neolithic Orkney? Researchers need to check for traces of pigment in artefacts and structures (and indeed on bones). Restraint is required in the initial cleaning of artefacts as recovered from the ground.
- •What use was made of pigments, other than to decorate structural stones?
- •What was used instead of pumice as an abrasive in inland sites? Was it sandstone or sand? Microwear analysis of artefacts might be able to shed light on this.
- •What was the function of the 'mystery objects'? If the crenellated stones had been used for threshing, how would this work?