Composition, Luminescence, and Color of a Natural Blue Calcium Carbonate from Madagascar

Abstract

Concerning the transparent blue calcite crystals of blue marble from Madagascar, this work suggests that their cavities, accessorial quartz, and marble stress textures do not provide unambiguous characterization of the blue color compared to other white marbles. It is suggested that the presence of stronium (∼850 ppm), barium (∼18 ppm), vanadium (∼10 ppm), and nickel (∼2 ppm) might be considered influential chromophores for the blue color. Blue marble aliquots were characterized to determine their mineralogical, textural, and chemical composition to elucidate luminescence spectra and the causes of the blue color by use of different techniques.