A Little Green Meteorite from Mercury

It's not quite the shade of the aliens from Toy Story 3, but it's close:

This odd rock is definitely from outside our planet, and the best hypothesis right now is that it's from Mercury. Its color comes from chromium and there's a lot of magnesium and calcium in it, but the weirdest thing is that it is almost completely devoid of iron. Iron is the most stable nucleus possible and there tends to be a lot of it in our rocks and normal asteroids. Although there's a lot of it around here, there's not a lot of it closer to the sun. Mercury is the best candidate for this profile of elements in the local environs (taking "local" somewhat loosely, of course).

So do we have a piece of rock that reflected traveling light ages ago -- a fragment of the messenger of the gods? Not sure yet, but there's several chemical tests to find out, detailed here. More to come ...