Coloration Mechanisms of Paleozoic Marbles of Central Anatolia: Mineralogical and Geochemical Evidence from White, Blue, and Grayish-Blue Calcites, Kırşehir, Türkiye

Blue calcite mineral formations occurring within Paleozoic marbles of Central Anatolia have been investigated in terms of their mineralogical and geochemical characteristics, as well as their potential for use as ornamental stones or decorative objects. XRD analyses of samples with different color tones (white, grayish-blue, and blue) revealed that the white sample contains only calcite, the grayish-blue samples include calcite and dolomite, while the blue sample contains calcite and quartz. XRF and ICP-MS analyses indicate a marked enrichment of trace elements such as Fe, Cr, and Ni in the blue sample, and Mn and Fe in the grayish-blue samples, suggesting these elements may influence the observed color variations. The presence of dolomite in grayish-blue samples and quartz in the blue sample corresponds to elevated MgO and SiO2 contents, respectively. Based on their distinct colors, textures, transparency, and other aesthetic properties, the grayish-blue and blue marbles show significant potential for use as decorative stones or ornamental objects.