To heat something by induction (which is and oscillating
magnetic field), the material has to react to the magnetic field.
As the magnetic field is made to oscillate, the molecules of the
material are pulled and vibrated in sympathy with the field and
their vibration energy increases.
Heat IS the vibration of molecules.
Thus induction heating will work on a magnetic material but will
have no effect on a material that is not magnetically
susceptible.