I’m not really sure you can explain quark confinement (which is what tim314 about: specifically if it was violated) without representation theory.
Basically, you’ve got three states a quark can be in, commonly called “red, green, blue”. There’s a symmetry acting that exchanges these states among themselves. Something might swap red and green, another swaps red and blue, the composition shuffles them all around (red->green->blue->red). The only states that you’re allowed to see in the real world are ones where the symmetry action does nothing.
Let’s label a quark state (fc), where f denotes a flavor (up or down, say) and c a color. The state (ur,ug,db), for instance, is one red up quark, one green up quark, and one blue down quark. If we swap green and blue, we get (ur,ub,dg), which is not the same state, so (ur,ug,db) isn’t allowed. However, we can superpose states. Consider
(ur,ug,db) + (ur,ub,dg) + (ug,ur,db) + (ug,ub,dr) + (ub,ur,dg) + (ub,ug,dr)
Now any shuffling of the colors merely swaps around terms in the sum, and so gives back the same state. This is an allowed state, which we call the proton.
Now a quark star can be composed of an awful lot of quarks with various flavor and color states such that the symmetry swapping around the colors leaves the total state invariant, but not one expressible as a simple collection of a bunch of nucleons (the distinction is subtle, but important). This would be seen as a blob composed of quarks as opposed to neutrons, but the state as a whole would not violate quark confinement.
If you grok neutron stars, thinking about one as sort of a giant atomic nucleus, you’re halfway there. A quark star isn’t just a giant nucleus, but more like a giant nucleon: something like a neutron blown up to a macroscopic scale. I think the most interesting thing about this would be that (at least as it seems to me) it’s essentially a quantum mechanical object at a macroscopic scale. In particular it has noticeable gravitational effects and may well be an useful object in studying the interaction between quantum mechanics and general relativity.