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Meteorite vs Magnetite: Streak, Magnetism and Interior Clues

Magnetite is one of the most common terrestrial materials mistaken for a meteorite because both can be dark, dense, and magnetic. Magnetism is therefore a screening clue, not a verdict. Magnetite normally produces a grey to black streak, while a fresh meteorite interior generally does not produce that strong dark mineral streak. Many stony meteorites contain small metal grains, but some meteorites are weakly magnetic or effectively non-magnetic. Use a non-destructive sequence first and seek qualified confirmation before cutting an important specimen. A strong grey-black streak supports magnetite, especially when the specimen is uniformly black inside and strongly magnetic. A possible meteorite needs a compatible set of clues such as an unusually dense, non-vesicular rock, a thin fusion crust or weathered equivalent, and small metallic grains in a fresh interior. No single magnet, streak, crust, or photo test confirms a meteorite. Photograph the object in place before cleaning it, record the location and surrounding material, and preserve any witnessed-fall information or chain of custody. Inspect the surface with a hand lens. Record crystal faces, granular ore texture, rust, a thin continuous crust, flow-like surface features, and any true gas-bubble holes without treating one feature as decisive. Test magnet response gently through a thin barrier so a strong magnet does not snap onto or scratch the specimen. Record strong, weak, localized, or absent attraction. If an inconspicuous expendable area is available, use clean unglazed ceramic. A strong grey-black streak supports magnetite; interpret a rusty streak cautiously because terrestrial weathering can affect meteorites. Do not cut a potentially important specimen merely for an app result. If a pre-existing fresh interior is visible, document whether it contains small metallic grains, a uniform black mineral mass, or obvious manufactured material. Compare the find with nearby rocks and known industrial fill. Magnetite-bearing rocks and slag can occur far from an obvious mine or furnace because aggregate and rail fill are transported. For a specimen that survives the screen, contact a geological survey, university, natural-history museum, or recognized meteorite specialist and retain the documentation and sample provenance. Do not assume every meteorite is magnetic or every strongly magnetic rock is a meteo