Clay-rich artefacts, including ceramics, are amongst the commonest and most abundant finds on archaeological sites.

Ceramics can be treated as sediments, indeed they are anthropogenically produced, thermally metamorphosed, matrix-supported 'rocks'.

Petrographical analysis of these artefacts, in terms of overall fabric and in terms of their four main components, namely plastic (clay), non-plastic including any intentionally added rock/mineral or organic matter (temper), crushed pot (grog) and void spaces, can help to define the amount and degree of raw material preparation and so give insights into the manufacture of the pot.

Petrographical analysis independently, or better alongside, geochemical analyses can suggest origins for the raw materials and so help provenance the ceramic.

Slips and glazes can also be recognised. Glazed pots are better investigated using polished thin sections, so that both transmitted and reflected light can be used in order to identify and describe the opaque phases within the glaze.

A selection of current and completed projects.

Neolithic to Romano-British coarse wares. Southwest England.
Bronze Age, including Beaker wares. Southwest Ireland, Central England.
Iron Age wares. Severn Valley, Pennines, Central England.
Bronze Age wares. Northern Italy.
Inka, Killke and Chimu-Inka wares. Peru.
Plains Indian Tradition. Central U.S.A.

Ross Island - Pot 16. Sherd number 651. Undecorated body sherd.

Bronze Age Food Vessel.

The sherd has a light brown (5YR 5/1) outer rim and a greyish black (N2) inner body therefore it is not totally oxidised. It is lightly gritted with angular to subrounded porphyritic basalt up to 2mm in diameter in a very dark matrix. The temper is essentially monolithic comprising non-ophitic ?Tertiary basalt with minor quantities of strained quartz (not carrying carbonate dust), plus spherulitic chert/?rhyolite. A few grains of magnetite surrounding a haematite core are present.

No grog was recognised.

The fabric suggests that crushed basalt was added to clean clay. This basalt does not compare with the Devonian volcanics of the Killarney region but might match one of the rare, local Carboniferous dolerites. More likely, however, the basalt is Tertiary in age from the north of Ireland. As the distribution of Tertiary basic rocks within the glacial fill of the Killarney area is not known, the possibility that this pot was locally made and tempered by a basaltic erratic cannot be discounted.

However, on balance, it is believed that this is an exotic pot of non-local manufacture and possibly from the north of Ireland.

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