For meteorite collectors, the question is always what the story is behind the fragment of rock which has by complete chance happened to come into the orbit of our small planet. Of course in most cases it is impossible to piece much of it together.
But in the case of spacerocks originating on other planets, when can work out something. If it originated on the moon or Mars then we can be sure that's where it came from because we've landed probes there and know the chemistry.
For similar reasons, it's sometimes possible to know the age of the meteorite, and even from how deep it was dislodged from on its home planet when chipped into space by another meteorite impact.
Naturally, fragments of Mars are particularly coveted, as only a handful of Martian material has ever been found on Earth.
So it's a rare opportunity which has recently arisen on the internet for a collector to own a relatively large piece of Mars - and by that we mean a 6.7g fragment (about the weight of a pencil).
Specifically, it is a fragment of Martain Basalt found in Morocco (the location is known, but not revealed, presumably because someone is hoping to find more).
The piece is greenish-brown and partially coated by desert Varnish; no fusion crust; cracks filled with terrestrial calcium carbonate, thin sock veins and small melt pockets are abundant. It consists of olivine in a fine grained groundmass of pyroxene crystals.
It carries a price of $3,350, which seems a substantial amount for something so small, but it is certain to retain a high value as an investment given the even paucity of supply. That, and it is the chance to hold a piece of another world.
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