Mass of Quark
The mass of the neutron is 939.565 MeV/c2, whereas the mass of the three quarks is only about 10 MeV/c2 (only about 1% of the mass-energy of the neutron). Like the proton, most of mass (energy) of the neutron is in the form of the strong nuclear force energy (gluons). The quarks of the neutron are held together by gluons, the exchange particles for the strong nuclear force. Gluons carry the color charge of the strong nuclear force.
Therefore, we have to distinguish between current quark mass (also called the mass of the ‘naked’ quarks) and constituent quark mass. Current quark mass refers to the mass of a quark by itself, while constituent quark mass refers to the current quark mass plus the mass of the gluon particle field surrounding the quark.
Noteworthy, because most of your mass is due to the protons and neutrons in your body, your mass (and therefore your weight on a bathroom scale) comes primarily from the gluons that bind the constituent quarks together, rather than from the quarks themselves. Mass is primarily a measure of the energies of the quark motion and the quark-binding fields any real object. It must be noted, gluons are inherently massless, they possess energy.