El azabache de Asturias: características fisico-químicas, propiedades y génesis.

This work shows the petrrographic and geochemical results obtained from the study of Asturian jet (Kimmeridgian, Jurassic) from Oles (Asturias, Northwestern Spain). By means of this research it was possible to determine the nature of this material, its composition and to explain its exceptional and anomalous properties. Asturian jet is a perhydrous coal, whose characteristics were promoted by the adsorption and retention of migrated hydrocarbons within its macromolecular structure in its early diagenetic stages. This gave rise to an anomalous evolution during the subsequent coalification processes. Moreover, the modification of its textural properties by the adsorbed hydrocarbons within the jet structure explains the great stability of this material which remains unaltered over long periods of time. [ABSTRACT FROM AUTHOR]