The Massive Prize Luring Miners to the Stars (bloomberg.com)

I chased down the wikipedia pages for some of the unimaginably highly valued meteorites in their pie chart (e.g. 511 Davida - [1]). The high value appears to be almost entirely a function of the enormous size of the larger ones - and these are all far from earth. I love the idea of space exploration but if you look at the elements in meteorite minerals [2] (I followed the links for those that did not have a formula in the table), apparently most of that value is in iron and nickel with some chromium, cobalt, manganese, scandium and titanium thrown in. Iridium is more highly concentrated than in the earth's crust but it is not clear that it is ever in a commercially viable extractable form. On first principles the emerging deep sea mining efforts would appear to have enormous seemingly impossible to beat advantages over mining in space. Not just in terms of distance etc logistics, but because deep sea vents have done such a great job of concentrating a much wider range of different more valuable elements in different places - and someone please correct me if I am wrong - there is no evidence of comparable processes separating out elements during the formation of the asteroids. (In this comparison I am admittedly not considering the hard to gauge environmental impacts of deep sea mining.)

1 https://en.wikipedia.org/wiki/511_Davida 2 https://en.wikipedia.org/wiki/List_of_meteorite_minerals

When they're talking quintillions, that's billion billions. Yes, truly staggering.

Also, consider the ecological effects. It may be wiser to coalesce material and fabricate structures as satellites than to import them onto the surface of Earth.

Assuming that "bringing it to Earth" means landing it on the surface, it'd have to be in truly ridiculous quantities to have any measurable effect – likely far more than the combined mass of everything mankind has and ever will place on Earth's surface.

If "bringing it to Earth" means placing asteroids in orbit, I'm less certain, but unless we're placing bodies around a third of the size of the moon or larger (really huge) in orbit there shouldn't be any notable effect from our point of view.