Quarks do have mass, which does make them fundamentally matter (as opposed to energy). A quark is never by itself, but is instead always found paired with another quark or an anti-quark. Quarks also possess a charge, as well as a spin, which is the motion in which the particle moves. Quarks obey laws at the quantum level; however, the effects of gravity are unpredictable on them due to their extremely small size.
Quarks are important to understanding quantum physics because they combine to make other particles. A quark paired with its anti-quark forms a meson, which is an extremely short-lived particle that has been observed in nature as the byproduct of cosmic waves. All other matter in the universe is formed from baryons, which is the combination of three quarks. Baryonic particles include neutrons and protons (but not electrons), the building blocks of the atom.
There are six types of quarks, each with a different mass and a charge that represented a third of a baryonic particle. The six types of quarks are up (with a charge of +2/3), down (-1/3), charm (+2/3), strange (-1/3), top (+2/3) and bottom (-1/3). Additionally, each type of quark has three different "colors," which describes how the quark is affected by forces at the quantum level (and has no actual relationship to colors that human beings see).
Quarks were originally proposed in 1961 by Murray Gell-Mann of the United States and Yuval Ne`eman of Israel. The name "quark" was given by Gell-Mann in 1964, and it comes from the James Joyce novel "Finnegan's Wake." Gell-Mann received the Nobel Prize in Physics in 1969. The theory of different types of "colors" was introduced in 1977, and the six different types of quarks have all been verified individually, with the last one being the top quark, which was proven in 1995.