| Hawthorne, Frank C., Cooper, Mark A., Grice, Joel D., Ottolini, Luisa (2000) A new anhydrous amphibole from the Eifel region, Germany: Description and crystal structure of obertiite, NaNa2(Mg3Fe3+Ti4+)Si8O22O2. American Mineralogist, 85 (1) 236-241 doi:10.2138/am-2000-0124 |
Caspar quarry, Ettringen, Vordereifel, Mayen-Koblenz, Rhineland-Palatinate, Germany