I learned this in Alaska and I love dropping this little factoid on people like a bombshell. Gold does not exist naturally on earth. All the gold accessible to us in mountains and rivers and inside ore is from meteorites. I'm so not kidding you!

Scientists did some calculations about how the Earth was formed and realized that all the precious heavy metals in the Earth's crust shouldn't be there. Back when our planet was molten, all the heavy gold and tungsten should have sunk to the core (where there's tons and tons of gold!)

But there is gold on the Earth's surface, so the scientists are obviously wrong -- UNLESS it came from out space!

The majority of scientists now believe that a huge asteroid shower early in the history of our planet pelted the Earth's crust with heavy metals from outer space that got mixed in with existing rock and is now available for mining or sifting!