Incorporating far-infrared data into carbonate mineral analyses

Abstract

Polycrystalline carbonate minerals (including calcite, Mg-calcite, and aragonite) can show distinctive variations in their far-infrared (FIR) spectra. We describe how to identify mixed-phase samples by correlating FIR spectral changes with mid-infrared spectra, X-ray diffraction data, and simple peak overlap simulations. Furthermore, we show how to distinguish portlandite-containing (Ca(OH)2 ) mixtures that are common in heated calcium carbonate samples. Ultimately, these results could be used for tracking how minerals are formed and how they change during environmental exposure or processing after extraction.