How to Tell If a Rock You Find Is a Meteorite
Have you ever found a strange rock while hiking and thought, “I bet it came from outer space!” I have. Unfortunately, it’s almost certainly not a meteorite. As cool (and lucrative) as it would be to accidentally find the remainder of a meteor that survived its journey through the atmosphere to crash into Earth, finding a real space rock is lucky to win the lottery. However, people who think they’ve found a meteorite are as common as socks. Still, it doesn’t hurt to check, so here’s a quick guide to whether this cool-looking piece came from outer space or if it’s just a dumb, boring Earth rock.
Meteorites are rare.
Research from the University of Manchester and Imperial College shows that around 17,000 meteorites, weighing between 50 grams and 10 kilograms, hit Earth each year, which may sound like a lot, but we’re talking about tiny objects randomly scattered all over the planet. Most of them fall into the oceans, and most of those that fall to the ground are small and unassuming, so the chances of you accidentally stumbling upon a meteorite and noticing it are low— only about 1,800 meteorites have been found in the United States. in the last two centuries. You better look for diamonds, gold and emeralds, which are more abundant than meteorites.
The best places to hunt for meteorites
Despite their rarity, people do find meteorites from time to time, but they usually look in the right places. The best place to look for space debris is Antarctica. Meteorites do not fall there more often than in other places, but dark blocks of stones and metal are more visible against the background of white earth. Other places meteor hunters might consider are the Mojave Desert in California and the Sahara in Africa. Think of dark areas on a light background.
How to understand that you have found a meteorite
If you manage to find an inappropriate stone while hiking in the desert, don’t get too excited. It’s probably not a meteorite after all. Here are some characteristics of meteorites and meteorites that will help you determine if you are truly lucky.
meteorites
True meteorites typically have the following characteristics:
- Melting crust : Meteorites are usually covered in an ash-black layer of molten rock caused by the intense heat generated as they pass through the atmosphere. While the color can change to a rusty brown after many years on Earth, the absence of something that looks like an alloy crust almost always means it’s not a meteor.
- Density : Meteorites are heavier than other rocks of the same size. Iron meteorites are 3.5 times heavier than ordinary terrestrial stone. Stone meteorites are about one and a half times heavier. But a piece of slag, a by-product of industry, is also heavy and much more common than a meteorite.
- Regmaglipts : Meteorites usually have a smooth surface, but they are often covered in regmaglipts, small depressions that look like someone has pressed their thumbs into wet clay.
- Magnetism : Most meteorites contain iron-nickel and attract a magnet. However, many earth stones, too. Magnetite and hematite are common, heavier than other rocks, magnetic, and can look like meteorites, so it’s not an easy process.
- Leaves no streaks : If you rub ordinary stones on the unglazed side of a kitchen or bathroom tile, it will leave a streak. There are no meteorites at all.
meteorites
If your stone has any of these characteristics, it probably isn’t a meteor:
- Roundness : Meteors are almost never round. They are irregularly shaped, as earthly forces like erosion have not touched them.
- Bubbles or Holes: Earth rocks often have bubbles or holes. There are no meteorites.
- Radioactive or Hot: Meteorites are almost always cold when they hit Earth. They do not kindle fire on earth. Travel through the atmosphere is fast and does not heat up the interior of the rock. They are also non-radioactive, so your Geiger counter is useless.
So now I have a meteorite?
If your stone passed all of these tests, it could be a meteorite, but it most likely isn’t. Many terrestrial objects can resemble meteorites. Slag is probably the most common meteorite irregular, but there are also basalt, iron ore, coal, bits of asphalt, charcoal briquettes, etc. Essentially, anything can be (and probably was) misunderstood by someone for the meteorite.
It’s hard to get a professional to take care of your little stone.
As hard as it is to find a meteor, it can be harder to find a geologist to help you identify it, so don’t take it to your local university and knock on the door of the geology department. The geologists had problems with people coming in and asking about the strange rock they found. Take a look at this terribly whimsical rant by lunar geochemist Randy L. Korotev of Washington University in St. Louis, which begins: “In 2022, I was contacted 5905 times by 2095 different people from 89 countries … Almost all of these people wondered if they had found bought or inherited a meteorite,” and ends with “Other meteorite scientists have the same experience and no longer answer questions from the public.”
But if you give people money, they’ll be happy to say you didn’t find the meteor. Prices vary from lab to lab, but it’s not incredibly expensive: The New England Meteorological Service, for example, will test a small sample of your rock for as little as $30. (I have no idea if they have a good reputation and I don’t recommend them – just to give you an idea of the price.)
Another option is to just tell everyone that you’ve found the meteor. If you are not friends with geologists, who will know about it?