The color of refractory organic carbon Maxime Debret, Yoann Copard, Antonin Van Exem, Geneviève Bessereau, Frank Haeseler and Jean-Noël Rouzaud BSGF - Earth Sci. Bull., 189 2 (2018) 9 Published online: 01 June 2018 DOI: 10.1051/bsgf/2018008