The gravitacional field is directly proportional to mass or inertia. It doesn't have another property or field like this, with this power.
I think that when we apply a force to an object, the resistance we feel is due only to the inertia of its gravitational field, and not to its material aspect. Consider for this that a star can lose all its material aspect to become a black hole of sheer gravity.
It may be that the equivalence between inertial mass and gravitational mass exists only because the gravitational field in these two cases is the same.
But if this is a true, then the idle energy required to produce a gravitational field as that found in a material object is E = mc², where m is the mass of this object. So everything is essentially gravity.
Did I make a mistake?