Meteorites Bits of asteroids, comets, or planets that manage to reach the ground without being burned up by passing through the atmosphere. One big meteor crater in AZ, the Barringer crater, is 1.2 kilometers across and 200 meters deep. Formed about 49,000 years ago. Meteorites will be dark, pitted, sort of melted looking. The metal content for some is high enough to attract a magnet.
Iridium shows up in meteorites, but it's uncommon on the Earth's surface.
Best places to find them are deserts and ice sheets, like Antarctica. There are primitive meteorites that are exactly the same as when they first condensed from solar nebula. Random mix of materials, rocky bits and metal flakes, etc. Some contain carbon compounds. Also one found in Morocco.