A magnetic study of Etruscan bucchero pottery: An application of rock magnetism to archaeometry

AbstractWe have applied techniques used in rock magnetism to the study of possible temporal changes in provenance and firing conditions of a collection of Etruscan bucchero pottery fragments representing the interval between 800 B.C. to 400 B.C. To our knowledge, this is the first time that such procedures have been applied to ancient ceramic wares. Our preliminary magnetic measurements demonstrate that this approach can provide useful archaeological information, as exemplified by the following results: (1) Bucchero ceramic styles sottile, spesso, and possibly pesante, contained magnetic particles of similar grain sizes, which suggested a common provenance and similar firing conditions for these pot typologies. (2) Ceramic styles buccheroid impasto and grey bucchero each had magnetic characteristics different from those in (1). However, too few samples of these were available for any definite conclusions. (3) The occurrence of magnetite, and not hematite, in all samples indicated that firing conditions were effectively reducing. (4) Variations in the amount of magnetite in different samples indicated that slight inhomogeneities must have existed in the iron oxide/hydroxide content of the local clay source.Most magnetic techniques are fast, easy, and generally nondestructive. Some magnetic properties, such as initial susceptibility, saturation remanent magnetization, and coercivity of remanence, can even be measured in the field. At the least, magnetic measurements can be used initially to discriminate among different groups of potsherds. Selected samples can then be analyzed with more elaborate methods of archaeometry.