Obsidians Optical Properties as a Provenance Determination Method

MARÍA VICTORIA FERNÁNDEZ; LEAL PABLO R.

ARCHAEOMETRY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014 vol. 56

0003-813X

This paper aims to evaluate the optical properties of natural rhyolite obsidians that might be useful to identify different sources of archaeological samples. Even though colour, degree of alteration, crystaloclast composition and textures are important properties to identify sources, all these features do not always lead to an unambiguous distinction. In this regard, refractive index (ND) becomes a helpful tool because it is not only sensitive to the chemical composition of natural glasses but also to their different thermal histories. Obsidians from six localities of Patagonia were analysed. Their refractive index measurements (ND) range only between 1.47 and 1.49, but ND of some of these sources is sufficiently constrained to allow discrimination between them.