Alcide d’Orbigny was a French naturalist who explored South America from 1826 to 1833. The 16.55kg meteorite was found near the Argentine settlement that bears his name, about 500 km southwest of Buenos Aires.
Angrites are very old achondrites and probably come from a large parent body. They have a wide distribution of cosmic ray exposure ages suggesting that the parent body or fragments of it might still exist. Candidates include the asteroids 289 Nenetta, 3819 Robinson, 5261 Eureka and the planet Mercury. Eureka is a Mars trojan orbiting in its trailing Lagrangian point. Other smaller bodies at L5, might be rubble detached from Eureka by its fast spin. Rotational period is just 2.69 hours.
Angrites are igneous rock consisting of laths of plagioclase, augite, a pyroxene containing calcium and, in this case, some titanium and aluminum and olivine.