Citation: Hawthorne, F. C.; Cooper, M. A.; Grice, J. D.; Ottolini, L. (2000). A new anhydrous amphibole from the Eifel region, Germany: Description and crystal structure of obertiite, NaNa2(Mg3FeTi)Si8O22O2 Note: M1A and M1 are interchanged in the bond length table. American Mineralogist, 85, pp. 236-241.