Casting Object to Material

Hi guys, I'm having error while casting object to material.

 InvalidCastException: Cannot cast from source type to destination type.

What I'm trying to do is something like this:

 mTarget.mMaterial = (Material)EditorGUILayout.ObjectField("Material", mTarget.mMaterial, typeof(Object));

I'm setting an object field in the Editor and it would be taking all the materials, so at the end I need to cast it back to material type.

Is there any solution for this?