Apollo astronauts brought 381 kilograms of moon rocks back to Earth. It is currently illegal to sell these rocks, but you can still own a piece of the moon for the right price. That's because there are also 370 known meteorites on Earth which originally came from the moon.
682
There are 277 known meteorites on Earth that originally came from Mars but none that came from Venus.
683
The world's rarest rock may be NWA 7325, a meteorite which is thought to have once been part of the planet Mercury. If this is true, it is the only piece of Mercury known to exist on Earth.
684
Norway's oil fund owns 1.4% of the global stock market.
685
There are 130 women for every 100 men studying at U.S. universities.
Fact #683 has been disproven since at least 2017. Multiple studies have concluded that NWA 7325 is at least 100 million years to old to have originated from Mercury, since Mercury hadn't crystalized yet.
#685 I'm not surprised that there are more women overall but the divides by subject are pretty startling... In my subject (modern languages) only about a third of students in the UK are men. I think this is similar across the humanities, but in the sciences, it's more the opposite.