Rock IdentifierMeteorites vs Meteor-wrongs
Key takeaways
- Most meteorites are denser than normal rock and many are magnetic (iron-rich).
- A dark fusion crust and, in iron meteorites, a Widmanstätten pattern are key signs.
- Slag, magnetite, hematite, and industrial waste are the usual 'meteor-wrongs.'
What meteorites are
Meteorites are rocks that survived a fall from space. They come in three broad types: stony (the most common), iron (dense, metallic), and stony-iron (a mix, including the beautiful olivine-studded pallasites). Genuine finds are rare, and misidentified earth rocks — jokingly called 'meteor-wrongs' — vastly outnumber real ones in people's pockets.
Signs that point to real
No single test is proof, but these traits raise the odds:
- Density: most meteorites feel unusually heavy for their size
- Magnetism: many contain iron-nickel metal and attract a magnet
- Fusion crust: a thin, dark, sometimes matte 'burnt' rind from atmospheric heating
- Regmaglypts: shallow thumbprint-like dents on the surface
- No vesicles: real meteorites lack the gas bubbles/holes seen in slag and lava
Common impostors
Frequent 'meteor-wrongs' include industrial slag (bubbly, glassy, lightweight), magnetite and hematite (magnetic but leave a black or red streak — meteorites generally don't streak), and man-made iron. A streak test helps: rub it on unglazed tile — a strong red or black streak points to an earth mineral, not a meteorite.
Confirming a suspect
For iron and stony-iron meteorites, cutting and etching a polished face can reveal the Widmanstätten pattern — interlocking crystal bands that only form over millions of years of slow cooling in space and cannot be faked. If several signs line up, a university geology department or meteorite lab can give a definitive answer; a phone photo cannot.
