Until I became the mother of boys, I never imagined how many pieces of nature would end up in my pockets, bag, car, and home. Now, there are sticks, rocks, leaves, and any number of unidentifiable “cool things” lying around, and sure…maybe some of those rocks could actually be meteorites?
If you’re like me (or just enjoy collecting “cool things” yourself), here’s how you can tell rocks from meteorites – and how to know whether or not you’re actually allowed to keep what you find, too.
Meteorites are fragments of meteoroids, asteroids, or even comets that chip off when they pass through a planet’s atmosphere.
There are three main types: iron, stony-iron, and stony, and each type has its own subgroups. They’re classified based on mineral content, structure, and chemical makeup.
The first thing you can do to test that “rock” you found is to measure density. Meteorites contain metallic iron, making them significantly heavier than a similarly-sized normal rock.
The materials are also often magnetic, though some of the rarer types may not be so it’s not a hard and fast rule.
Meteorites are also often melted into odd shapes, thanks to the heat of passing through Earth’s atmosphere, and could contain pits called regmaglypts in their surface. They look a bit like fingerprints pressed into clay.
The melting process could also form a “fusion crust,” which resembles a black eggshell-like outer crust. The newer the meteorite, the shinier it will typically be.
You might also see lines in the surface as thin as a human hair. These are called flow lines, and are also caused by melting.
Another test you can try is scratching it along an unglazed ceramic surface; if your rock leaves a black or red streak, it’s probably just a rock.
Instead of looking for signs of a meteorite, though, it’s honestly probably easier to prove that they’re not from outer space instead.
A meteorite won’t contain crystals, like quartz, and they’re unlikely to feature any kind of bubbles or vesicles (the pin-prick holes typical to pumice).
If you’ve done all of these and think you have a meteorite, you’d still have to have it tested by a lab to be 100% sure.
Be careful who you show it to, though – if you find it on public land, it belongs to the United States Government or the Smithsonian Institute.
Happy rock hunting, friends.
May we all come home with “cool things” at the end of the day.
