Citation: Salviulo, G.; Princivalle, F.; Demarchi, G.; Fabro, C. (1992). Effects of Ca-Mg substitution in C2/c pyroxene structure on natural clinopyroxenes from spinel peridotite nodules (Pico Cabugi, Brazil) Sample: PC135 Note: z-coordinate of O2 altered to match reported bond lengths. Physics and Chemistry of Minerals, 19, pp. 213-219.