How to Tell If a Rock Is a Meteorite
Most rocks people suspect are meteorites turn out to be ordinary Earth rocks. A few simple checks rule out the large majority, and the ones that pass are worth taking further.
A real candidate is usually heavier than it looks, responds to a plain magnet, has a thin dark surface rind, and shows a gray interior with fine metal flecks. It has no quartz, no gas bubbles, no layering, and no glittery crystals. A red streak on unglazed tile rules a rock out on its own. Even a rock that passes every check is only a candidate until a laboratory tests it.
Add a photo and the optional analysis weighs the specific features for and against your rock, for a sharper read.
This guide walks through the same checks the free Meteorite Check screening runs, in plain language. None of these tests confirms a meteorite by itself. They work together: a candidate has to clear the rule-outs and then show several positive signs at once. Work through them in order.
The checks that matter
01 Magnet response
Most meteorites contain metallic iron and pull on a magnet. Use a cheap ceramic magnet or a compass needle, not a strong rare-earth magnet. A rare-earth magnet is so strong it sticks to many ordinary Earth rocks and gives false positives.
A response is a positive sign, but it is not proof. Two common Earth minerals, magnetite and hematite, are also magnetic. Magnetism alone never identifies a meteorite.
02 Weight for its size
Meteorites are usually denser than ordinary rock, so a real candidate tends to feel heavier than a same-sized rock from your yard. This heft comes from iron and nickel metal and from dense minerals.
Heft is a supporting sign, not a deciding one. Earth minerals like hematite and magnetite are also dense and heavy.
03 Fusion crust
As a meteorite falls, its surface melts and forms a thin dark rind called fusion crust. On a fresh fall it is glossy black. After years on the ground it weathers to dull brown. The crust is thin, on the order of a millimeter, and sits over a different colored interior.
A thick rusty shell, paint, or a coating that is the same material all the way through is not fusion crust.
04 Regmaglypts (thumbprints)
Many meteorites carry shallow rounded depressions that look like thumbprints pressed into clay. They form as softer material ablates away during the fall. Deep angular holes, hollow pockets, or a sponge-like surface are not regmaglypts and usually point to slag or industrial material.
05 The streak test
Drag the rock across an unglazed white ceramic surface. The underside of a toilet tank lid or the unglazed foot ring on the bottom of a mug or plate works well. The color of the powder it leaves is the streak.
A red or red-brown streak means hematite, an Earth mineral. That rules the rock out on its own. A black or dark gray streak is a strong negative for most rocks, but it is not an absolute rule-out, because some genuine meteorite types can leave a dark streak. A meteorite that contains plenty of metal often leaves little or no streak at all.
06 The interior, if it is cut or broken
If a window is already cut or the rock is broken open, the inside tells you the most. Do not cut a whole specimen yourself if you might want it tested or sold, since an intact crust has value. A stony meteorite interior is typically gray and fine grained, often with small round grains called chondrules and with bright metal flecks scattered through it.
The interior also shows the clearest rule-outs, covered next.
What rules a rock out
Some features are not just weak signs, they are reasons to stop. If you see any of these, the rock is almost certainly not a meteorite.
- A red streak. Hematite leaves a red streak and is a very common meteorwrong. This is a hard stop.
- Gas bubbles or vesicles. Holes left by trapped gas mean the rock formed in air, as terrestrial lava or as slag. Space has no atmosphere to form bubbles, so meteorites do not have them.
- Quartz. Quartz is an Earth mineral and is not found in meteorites. Glassy, see-through, or milky grains point to an Earth rock.
- Layering or banding. Sedimentary layers or banded structure form on Earth over time and are not a meteorite feature.
- Glittery crystals on the outside. Meteorites have no sparkly crystal coating. Surface sparkle is usually mica, quartz, or pyrite, all of them terrestrial.
The common meteorwrongs
The word meteorwrong is what dealers and collectors call a rock that looks promising but is not a meteorite. A handful of materials account for most of them.
| Material | Why it fools people | What gives it away |
|---|---|---|
| Hematite | Heavy, can be dark, often magnetic | Red streak on unglazed tile |
| Magnetite | Heavy and strongly magnetic | Black streak, no fusion crust, often crystal faces |
| Slag | Dark, heavy, melted-looking, often magnetic | Gas bubbles and a spongy holey texture |
| Industrial iron | Metallic, magnetic, dense | No nickel, often a regular shape or machining marks |
| Basalt and other lava rock | Dark and dense | Vesicles, no fusion crust, no metal flecks |
Not sure which way yours leans?
The free Meteorite Check screening walks you through these checks and gives an honest result in a couple of minutes. Strong candidates get pointed to a partner laboratory.
See which features help or hurt your rock
The free screening scores your answers. Add a photo and the optional analysis reads the rock itself, feature by feature. It calls out the specific signs that raise its potential, a dark fusion crust, bright metal flecks, or chondrules on a cut face, and the specific signs that count against it, gas vesicles, quartz, layering, or surface sparkle. You get the reasons behind your result, not just the number.
It works with the screening, not around it. It adds detail and explains your result. It cannot turn a look-alike into a meteorite, and only a laboratory can confirm a real one.
Add a photo in the app. From $1.99. No subscription required.
If your rock passes the checks
A rock that clears every rule-out and shows several positive signs is a real candidate, and that is worth acting on. It is still only a candidate. Visual checks cannot confirm a meteorite, and even careful screening can only flag one.
Confirmation comes from a laboratory. A meteorite is officially recognized once it has been classified and published in the Meteoritical Bulletin Database, the accepted record kept by the Meteoritical Society. For iron-rich candidates, a laboratory test for nickel is a strong filter, since meteoritic metal always contains nickel and most man-made metal does not.
If you want to compare your find against the real thing, Treasure Coast Meteorite Co. carries authentic specimens, both classified meteorites with published references and verified unclassified material. You can read more on identification or browse the collection.
Common questions
- Do meteorites stick to a magnet?
- Most do, because most contain metallic iron. Use a plain ceramic magnet or a compass, not a rare-earth magnet, which is strong enough to grab many ordinary rocks. Magnetism is a positive sign but never confirms a meteorite on its own, since hematite and magnetite are also magnetic.
- Are meteorites heavy?
- Usually heavier than a same-sized Earth rock, because of their iron and nickel content. Heft supports a candidate but does not decide it, since some Earth minerals are dense too.
- Can a meteorite have holes or bubbles in it?
- No. Holes left by gas bubbles, called vesicles, form in air. They are a sign of terrestrial lava or slag. Meteorites do not have them.
- My rock is heavy and magnetic. Is it a meteorite?
- Not necessarily. Heavy and magnetic also describes hematite, magnetite, slag, and industrial iron. You need to clear the rule-outs, such as the streak test, and see several positive signs together before a rock is a real candidate.
- How do I get a meteorite confirmed?
- Only a laboratory can confirm one. A meteorite is officially recognized once it is classified and published in the Meteoritical Bulletin Database. Screening can flag a candidate and point you to a laboratory, but it cannot confirm one.