Finding a rock from space is a real possibility. Meteorites land all over the world, and some of the best-known were found by farmers, hikers and people clearing their gardens. But it's worth starting with honesty: the great majority of rocks that people suspect are meteorites turn out to be ordinary Earth rocks or industrial slag. Collectors even have a name for them: meteorwrongs.
The good news is that a few simple checks will rule most of them out quickly, and they'll tell you whether your find is worth sending to an expert.
The three main kinds of meteorite
Knowing what you're looking for helps:
- Stony meteorites are the most common kind to fall. Most are chondrites, which contain small round grains called chondrules and specks of iron-nickel metal. They can look surprisingly like Earth rocks once weathered.
- Iron meteorites are made mostly of iron-nickel metal. They are very heavy, strongly magnetic and often rusty brown on the outside.
- Stony-iron meteorites, such as pallasites, are a mix of metal and stone. They are rare.
1. Look for a fusion crust
As a meteoroid races through the atmosphere, its outer surface melts. When it slows down, that melted layer hardens into a fusion crust: a thin dark skin, usually black or dark brown, often only a millimetre or so thick.
- A fresh fusion crust is black and can be matte or slightly glossy, sometimes with fine flow lines.
- On an older find it weathers to rusty brown.
- If a corner is chipped, the interior often looks quite different from the crust: lighter grey in a stony meteorite, or shiny metal in an iron.
A dark, shiny surface on its own isn't proof. Desert varnish, river polishing and iron staining can all give Earth rocks a dark coat. The difference is that a fusion crust is a thin shell over a different-looking interior.
2. Check the weight
Meteorites are usually heavy for their size. Even stony meteorites contain metal, which makes them denser than most common Earth rocks. Iron meteorites are far heavier still, roughly three times the weight of a typical rock of the same size.
Hold your stone in one hand and a similar-sized ordinary rock in the other. If yours doesn't feel noticeably heavier, it's very unlikely to be a meteorite. Density is one of the most reliable home checks; how to identify a rock explains how to judge it by hand.
3. Test it with a magnet
Most meteorites contain iron-nickel metal, so most will attract a magnet. Use a strong magnet, ideally a small neodymium magnet hung on a string, and see whether it's pulled toward the stone.
- Iron and stony-iron meteorites attract strongly.
- Most stony meteorites attract noticeably, because of the metal flakes they contain.
- A few rare types, including some meteorites from the Moon and Mars, are only weakly magnetic or not at all.
Magnetism alone doesn't prove anything, though. Many Earth rocks and minerals are magnetic too, including magnetite, some basalts and plenty of man-made iron. A magnet is a way to rule things out, not to rule them in.
4. Look for thumbprints, not bubbles
Many meteorites, especially irons, have shallow, rounded depressions on their surface called regmaglypts. They look as if someone pressed their thumbs into soft clay. They form as the surface melts and ablates during the fiery fall.
Bubbles are a different matter. Meteorites almost never contain gas holes (vesicles). A rock full of round holes is far more likely to be volcanic, such as scoria or vesicular basalt, or industrial slag, which is very often bubbly. This is one of the most useful ways to rule a stone out.
5. Do a streak test
Rub the stone on the unglazed back of a ceramic tile, choosing an inconspicuous spot.
- Most stony meteorites leave little or no streak, or a faint grey one.
- Hematite leaves a distinctive red-brown streak.
- Magnetite leaves a black streak.
Hematite and magnetite are the two most common meteorwrongs. Both are heavy, dark and often found as rounded lumps, and magnetite is strongly magnetic. A red-brown or black streak points firmly toward one of them rather than a meteorite.
6. Look inside, if a corner is already broken
Don't break or cut a suspected meteorite yourself, as it can reduce its scientific and collector value. But if a corner is already chipped, look at it with a magnifier:
- Stony meteorites often show tiny bright metal flecks scattered through a grey interior, and sometimes small round chondrules.
- Iron meteorites look like solid metal. When cut, polished and etched in a lab, many show a crisscross pattern called the Widmanstätten pattern, which forms only during extremely slow cooling.
Common meteorwrongs
| Suspect | Why it fools people | What gives it away |
|---|---|---|
| Industrial slag | Dark, heavy, sometimes magnetic, often found near old mines, railways and foundries | Bubbles and glassy patches, swirls, often lighter than expected |
| Magnetite | Heavy, black, strongly magnetic | Black streak; crystalline interior, no fusion crust |
| Hematite | Heavy, dark, rounded | Red-brown streak; usually not magnetic |
| Basalt and scoria | Dark, sometimes slightly magnetic | Often has gas bubbles; fine crystals all through |
| Iron concretions and manmade iron | Rusty, heavy, magnetic | Layered shells, or shapes and textures of worked metal |
| River-polished dark rocks | Smooth dark surface | Same colour and texture inside as outside |
The nickel test is lab territory
Almost all meteoritic metal contains nickel, while most man-made iron and Earth rocks have little or none. Testing for nickel is therefore a strong indicator, but doing it reliably requires chemical reagents or lab instruments, and it still isn't conclusive on its own. Confirming a meteorite properly involves examining a thin slice, measuring its chemistry and comparing it against known meteorite types. That's work for a specialist lab, not a kitchen table.
How to get it verified
If your stone passes the basic checks (heavy, attracts a magnet, no bubbles, no red or black streak, a thin crust over a different interior), it's worth asking an expert.
- Photograph it from several sides with a ruler for scale, plus close-ups of the surface and any broken area.
- Weigh it and note its dimensions.
- Write down where and when you found it, as precisely as you can. Location data matters a great deal for science.
- Contact a university meteorite lab or a natural history museum. Several universities with planetary science or meteoritics departments offer identification help, and most ask you to send photos and your test results by email first.
Confirmed new meteorites are formally classified and given an official name through the Meteoritical Society, after study by a recognised lab.
Tip: don't clean a suspected meteorite with water, wire brushes or chemicals. Moisture speeds up rusting of the metal inside. Keep it dry, in a bag or box, and handle it as little as possible.
A note on ownership
Laws about who owns a meteorite vary by country, and sometimes by region or type of land. In some places a meteorite found on public land belongs to the state. Check local rules before selling or exporting one.
A photo app like AI Stone can suggest what a dark, heavy stone most likely is and list its expected streak, magnetism and density, which is handy for spotting a meteorwrong early. No photo can confirm a meteorite, though. For a possible one, a specialist lab is the only real answer. If you'd like to know what else might make a find worth something, see is my rock valuable?