A fabric is characterized by the nature of the raw material, a clay mixed with inclusions (non-plastic minerals). This raw material generally reflects a production region, or in some cases a group of workshops.
The fabric can be characterized by different levels of macroscopic, petrographic and geochemical analysis. The macroscopic level corresponds to an observation with a binocular magnifying glass (x10-40) on fresh break. It includes a definition of the colours of the paste and the surface, and especially of the minerals of sand size (4 to 1/16 mm). The nature, size, frequency, shape, homogeneity of minerals are the key variables. The petrographic analysis, on a thin section, concerns the same data and both approaches must lead to the same characterization.
Geochemical analysis is an archaeometric approach, using physical instruments (Spectrometry, X-Fluorescence, …) to determine the proportion of major, minor and trace chemical elements, and thus a precise identity of the fabric.