The gravitational instability of free and dilute Newtonian boson clouds has been examined. For collisionless Newtonian boson clouds with a uniform unperturbated Bose gas density, it is deduced that the gravitational instability will never give rise to the formation of boson stars, but only black holes; however if the unperturbated density, in the neighbourhood of the perturbation, has a scale length equal to or smaller than the perturbation wavelength, the formation of free Newtonian boson stars could also be possible. For dilute Newtonian boson clouds it is shown that the gravitational instability can lead the cloud to condense into boson stars of different masses but identical radii, in agreement with studies about equilibrium configurations of dilute Newtonian boson stars. The galactic distribution of these Newtonian boson stars, and hence, the average distance among them is also discussed.