Internet Archaeology. 9. Mason & Gonnella. 3.

3.0 Methodology

Specifics of the methodology of this study are more fully explained elsewhere (Mason 1994). One major difference between this study and those petrographic studies undertaken on other types of pottery, is that the material here consists of the quartzose stonepaste type of ceramic body. The stonepaste mixture may be described as comprising about eight to ten parts quartz, one part crushed glass, and one part fine white clay. The clay keeps the material together during forming, and combines with the glass during firing to cement the quartz grains together (Mason and Tite 1994).

This simple description of the body as comprising quartz, glass, and a little clay provides a challenge to any form of physical characterisation. However, the successful application of ceramic petrography has been made possible through the development of a set of criteria for differentiation of quartz-rich bodies (Mason 1995).

Although in many other studies it is preferable to talk of 'characterisation' rather than 'provenance' studies, the well-developed ceramic industry of the Islamic world, with few large centres producing typologically and petrographically distinct products, makes the attribution of 'provenance' meaningful. However, certain assumptions must be made explicit. Firstly, all samples with 'the same' petrofabric are considered to have the same origin. Evidence to date indicates that this is a very sound assumption with regard to the wares discussed in this paper, but it should be recognised that when an attribution is made, it is considered to represent a statistically high probability of being correct, and is not absolute. Secondly, production centres are typically characterised by analysis of evidence of manufacture, such as wasters (pottery ruined in the firing) or kiln-furniture. In the cases of all the 'reliably' attributed petrofabrics in this paper, none of the wasters was found directly in association with a kiln, and it is conceivable that pottery warped and fused together by heat could result from causes other than accidents in the kiln. However, in every case that samples identified as wasters by the analyst in this paper have been subjected to petrographic analysis, they have produced a petrofabric which is distinct from those wasters found at other sites.