An achondrite is a stony meteorite that is made of material similar to terrestrial basalts or plutonic rocks . Compared to the chondrites , they have all been differentiated and reprocessed to a lesser or greater degree from the effects to melting and recrystallization on or within meteorite parent bodies . It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies .