The meteorites that land on earth can be made of stone, iron or stony iron. A few meteorites are made of volcanic glass, but scientists aren't sure that all of these meteorites are extraterrestrial in nature. They believe some of these meteorites are formed when material from an impact crater liquefies and then turns to glass as it's ejected into the atmosphere.
Stony meteorites are called aerolites. Stony iron meteorites are called siderites, and iron meteorites are called siderolites. Meteorites made of volcanic glass are known as tektites.
Before a meteorite reaches the earth it's called a meteor, and most are so small that they burn up before they land. Still, thousands of meteorites have been found on the surface of the earth. Most only weigh a couple of pounds. Very few meteorites have a weight that measures in the tons and most that do are siderolites. This might be because it's difficult to tell meteorites made of stone from the stones that occur naturally on earth.
Most scientists believe that the overwhelming majority of meteorites are ejected from asteroids. They can do this by retracing the trajectory of the meteorite back to its parent asteroid. The rest of the meteorites come from either the Moon or Mars.