Asteroid with $10 Quintillion Worth of Metals Edges Closer to US Reach
markets.businessinsider.com
markets.businessinsider.com
So a thousand thousand billion worth of Metals. Although the metals wouldn't worth as much if it ever reach earth due to supply and demand.
I do wonder though, apart from Gold ( which is arguable but let's ignore it ), do we really need that much Iron or Nickel?