Investigations of the temperature dependences of the magnetic permeability and dielectric permittivity in the temperature range 4.2 K less than or equal to T less than or equal to 300 K and the field dependence of the magnetization M(B) in fields B less than or equal to 50 T show that the magnetic properties of the complex (ET)(2)C-60 cannot be described on the basis of the standard model, which assumes that the paramagnetic oxygen impurity makes the dominant contribution. It is found that the magnetism in (ET)(2)C-60 is due to the diamagnetic properties of the C-60 and ET molecules and to specific paramagnetic centers of the type C-60(-), which possess an anomalously low g factor \g\approximate to 0.14. An experimentum crucis is proposed for checking the oxygen paramagnetic center model for pure C-60 films. (C) 1999 American Institute of Physics. [S0021-3640(99)01210-4].