A thread on this forum Plans for Asteroid Mining has more than 9000 views. From that I conclude that belief that asteroid composition must be highly varied mu thast be wide spread. I'm having a hard time understanding why that should be. So unless the planitesimals formed at approximately same radius from the sun, were varied in composition, how did the asteroids become varied? I would expect the original nebula to be pretty homogeneous at the same radius from the center of mass. Ditto for the planetesimals formed in that region. So how did the planetesimals and/or asteroids become so varied? Are there other Wikipedia articles relevant to this that I haven't found yet?