Base de minéraux et lithothérapieMinérauxColumbite-(Mg)Robert M. Lavinsky·CC BY-SA 3.0·WikimediaColumbite-(Mg)MgNb2O6Ortorombico root IMA renamedCompositionComposizione (% in peso)NbOMgNbNiobium60.7%OOxygen31.4%MgMagnesium7.9%