All but one other have been part of the Shergottite, Nakhlite and Chassignite
group, named for the locations where the first of each subtype was discovered.
These "SNC" meteorites (an acronym derived from three of their types: shergottite, nakhlite, chassignite
) are igneous rocks similar in many respects to the rocks that comprise the floors of the Earth's ocean basins.
They come in three different groups, the shergottites, the nakhlites and the chassignites
. Of most interest for the question of water on Mars are the nakhlites, because this group of Martian meteorites contains small veins, which are filled with minerals formed by the action of water near the surface of Mars," he said.