No human has ever set foot on Mars, no spacecraft has ever returned from Mars, and only two spacecraft ever landed safely on Mars. But the idea that some meteorites come from Mars, first suggested in 1979, is now accepted by most planetary scientists. Most likely, they come from asteroids, which circle the Sun between the orbits of Mars and Jupiter. Some meteorites are almost certain to come from the asteroid Vesta. Most of the stony meteorites are chondrites, collections of the dust, sand, and gravel that orbited the Sun before the planets and asteroids formed.
Most achondrites are basalts or breccias of basalt fragments and look very much like Earth basalts.
A dozen of the meteorites that have been analyzed are from the Earth's Moon. They were compared with Moon rock samples brought to Earth by the Apollo astronauts and the Luna robots, and they were found to be essentially identical. Without the Apollo and Luna samples from the Moon, we might still be arguing about these meteorites. Since most meteorites are not similar to Moon rocks, scientists looked to other sources of rocks in the solar system. Asteroids, which are made of rock and come in different sizes, are the most likely sources of meteorites.