Similar to basalt. Similar to the Earth's oceanic crust. Age of all known meteorites is between 4.4 and 4.6 billion years. Meteorites represent primitive solar system material. Most is microscopic.
Meteorites are a significant addition to the amount of carbon on the Earth.
Meteorites were probably derived from a differentiated body which has been dirsupted by collisions. They contain no high pressure minerals, hence they are not derived from a large parent body. Probably come from once-molten asteroids. In 1970 about 2300 were known to exist. Now, more than 5000 have been found.