These beautiful combinations of metal
and gemlike crystals are called pallasites after Peter Simon
Pallas, the German naturalist who first described them in
1772. Pallasites contain roughly equal amounts of olivine,
a green-to-brown silicate mineral, and nickel-iron metal.
This association suggests that pallasites come from the boundary
region between an asteroid's metallic core and silicate mantle
where mixing of the two materials occurred.