A meteorite thought to be from Mars that was found at Allan Hills, Antarctica, in 1984. It is 4.5 billion years old, with minor, secondary veins about a billion years younger. NASA scientists at the Johnson Space Center reported in 1996 that fossil-like structures in ALH 84001, along with other evidence, indicated life on Mars. In particular, tiny magnetite crystals inside the meteorite have crystal forms like those produced inside bacteria on Earth. Whether or not this evidence proves that the rock, or Mars, once harboured life is still the subject of scientific debate.
http://curator.jsc.nasa.gov/curator/antmet/marsmets/alh84001/sample.htm NASA meteorite pages at Johnson Space Center include detailed information about the analysis of the meteorite from Mars, ALH84001. There are lots of pictures, plus articles about the search for past life on Mars.
Subjects: Astronomy and Astrophysics.