GeneralWesc was a little off when he said that quarks 'form all elementary' particles.
First off, the quarks ARE (some of) the elementary particles, and they combine in various ways to form the the next level up, the hadrons, or quark-aggregates, made up of either a quark and an antiquark (
mesons), or three of the same (
baryons) -- quark-quark-quark or antiquark-antiquark-antiquark. Here are some examples of hadrons:
The positive pi-meson is an up quark and an antidown quark.
The proton is two ups and a down
(each for a total charge of +1, see Jesler's post.)
There are two other types of fundamental entities, the
leptons and the
bosons. The leptons include the
electron, the
muon, and the tau lepton -- the latter two being
unstable more massive 'cousins' of the electron. Each of these three has an associated
neutrino (these neutrinos are also considered leptons). All six of these have an associated
antiparticle (just like with the quarks). On the other hand, there are the bosons. These are the particles which transmit the four forces of
nature. They are: the
photon (transmits the
electromagnetic force), the W+, W-, and Z bosons (transmit the 'weak nuclear' force which is responsible for certain types of nuclear decay), the
gluon (transmits the 'strong nuclear' force between quarks, and the force between the quark agreggates -- the '
hadrons' which include
protons and
neutrons, effectively holding atomic nuclei together), and finally the
graviton, the proposed but as-of-yet-unobserved carrier of the
gravitational force. Some physical theories include up to 12 other 'X bosons' which are not common in our cold boring universe because of their inherent high energy.
Once again, the leptons and the bosons are NOT quarks or made out of quarks, but they ARE fundamental
elementary particles. Together, quarks, leptons, and bosons make up all the
stuff in the
Universe.