NWA (North West Africa) 7533 was unearthed by Bedouin tribesmen in the Sahara desert. It is a highlands breccia, which sets it apart from all other Martian meteorites. A breccia contains thousands of fragments of different geological samples and is the geological equivalent of a library containing the early history of Mars.
“As it turns out the crust is very old – about 4,430 million years old, which means that everything was happening very fast in the beginning on Mars,” said Dr Alexander Nemchin from Curtin University, a team member and the second author of a paper published in the journal Nature.
Humayun M et al. 2013. Origin and age of the earliest Martian crust from meteorite NWA 7533. Nature 503, pp. 513–516; doi: 10.1038/nature12764