meteorite
Fragment of rock, iron or another mineral that crashes into Earth instead of completely burning up as it crosses the atmosphere.
iron meteorite 
Meteorite consisting mainly of iron and nickel, marked by small faults.
stony-iron meteorite 
The rarest class of meteorites, characterized by the presence of almost equal quantities of rocky matter and metals.
achondrite 
Meteorite whose composition is similar to that of certain terrestrial rocks; believed to come from the Moon or from Mars.
chondrite 
The most common meteorite, characterized by the presence of rock or sulfurous matter in the form of minuscule spheres (chondrules).
stony meteorites 
Meteorites composed mainly of rocky matter. Divided into two groups: chondrites and achondrites.