Physicochemical, Petrographic and Mineralogical Studies of Lublin Amber

Abstract

This study presents, for the first time, the results of research on Lublin amber and the associated glauconite and sandstones accompanying amber deposits. The material was collected directly from mining excavations. Comprehensive analyses were performed on glauconite, sandstones, and amber samples taken from the excavation walls of the Stellarium mine (Górka Lubartowska-Niedźwiada deposit). The article includes petrographic and mineralogical characterization of glauconite and sandstones. FTIR spectroscopic analyses were conducted on amber samples obtained from the bottom, middle, and top sections of the deposit series, as well as from sandstones of varying hardness (hard, medium, soft). FTIR results did not reveal a clear relationship between the degree of amber depolymerization and its position in the profile, nor between the content of C=O and C–H bonds and the hardness of the host rock. However, a distinct increase in C=C bond content was observed in amber extracted from harder sandstones, which may indicate partial degradation of the polymer network leading to reduced crosslinking. AFM nanomechanical tests showed that amber from hard sandstones exhibits higher stiffness and brittleness with a simultaneous decrease in elasticity. Minor differences in elasticity values were also noted depending on sampling depth and amber color, with milky varieties showing higher Young’s modulus values. The obtained results provide a basis for further research on the genesis of Lublin amber and its distinctiveness compared to other varieties of succinite (Baltic amber).