Citation: Gasparik, T.; Parise, J. B.; Reeder, R. J.; Young, V. G.; Wilford, W. S. (1999). Composition, stability, and structure of a new member of the aenigmatite group, Na2Mg4+xFe2-2xSi6+xO20, synthesized at 13-14 GPa. American Mineralogist, 84, pp. 257-266.