Universe Today
"[The Trojan family] is unique in the Solar System, in more ways than one. Unlike every other family that exists in the Main Asteroid Belt between Mars and Jupiter, it is made up of olivine-rich asteroids. Also, the asteroids are < 2km across, much smaller than we can see at other families, basically because they are much closer to the Earth than other asteroids. Finally, it is the closest family we know to the Sun, and this has implications on how it formed in that the tiny but continuous action of sunlight may have played a role."
"The presence of asteroids with exposed olivine on their surfaces constrains the sequence of events that led to Mars' formation. Olivine forms within objects that grew large enough to differentiate into a crust, mantle and core. Therefore, these objects must have formed before Mars did and were available to participate in Mars' formation. To expose the olivine, it is necessary to break these objects up through collisions. Our ongoing work indicates that this is unlikely to have happened after the Solar System settled down in its current configuration, therefore there must have been period of intense collisional evolution during the planet formation process."