I recently noticed that the density of an electron, assuming it is a particle, was e21 gm cm3. This is e7 x more than a neutron star 2 x e14. I then looked up quarks. The up quark is the most dense (mass = 9 x e-27 gms, radius .5 x e-17 cm) with a density e5 x the electron or 1.7 x e25. Thus, a quark is e12 x more dense than a neutron star. Is this correct??