No, quarks do not violate the quantization of charge. The quantization of charge is a fundamental principle in physics, stating that electric charge is always observed in discrete multiples of a fundamental unit of charge. In the case of elementary particles like quarks, their electric charge values are quantized.
Quarks have fractional electric charges, which might seem to contradict the idea of charge quantization at first glance. However, quarks are never observed in isolation due to confinement, as mentioned earlier. They are always found bound together in combinations that result in integer charge values for composite particles such as protons and neutrons.
For example, quarks come in different flavors: up, down, charm, strange, top, and bottom. Up quarks have a charge of +2/3, while down quarks have a charge of -1/3. By combining three quarks of appropriate charges (two up quarks and one down quark), we obtain a proton, which has a charge of +1, or by combining three down quarks, we obtain a neutron, which has a charge of 0.
So while the individual quarks themselves have fractional charges, their combination in composite particles always results in integer multiples of the elementary charge, thereby preserving the quantization of charge.