A brief summary of the wealth that lies unclaimed in the Asteroid belt between Mars and Jupiter.
Link: Wiki on Psyche 16
Link: Wiki on Asteroid Mining
Note that Psyche 16 is an M-Type Asteroid, being comprised almost entirely of heavy metals. Most of the precious metals on earth have already sunk through the crust and into the core, the possibility or theory then that Psyche 16 is a relic core from a planet implies that it is laden with precious metals.