Identification of common minerals using stoichiometric calibration method for dual-energy CT

Medical X-ray computed tomography (CT) can be used to rapidly and non-destructively characterize structure and density variations of geological specimens. More information about the nature of samples (electron density and elemental composition) can be retrieved using multi-spectral approaches. This paper explores one of them, a stoichiometric calibration method for dual-energy imaging, to identify the most common minerals. A set of 18 calibrating materials was selected to cover a range of variability in effective atomic number (Z(eff)) and electron density (rho(e)) encountered in geological specimens. The validation of this calibration was performed analyzing 23 common minerals by mapping their respective Z(eff) and rho(e) in order to identify the one with the closest properties. This study shows that the stoichiometric method correctly identifies the most important and common minerals (quartz, calcite, dolomite) that are usually not distinguishable using a single energy imaging method, although all the 23 studied minerals were not correctly determined. We show that this method previously elaborated for medical purposes is also efficient in earth science