Are all meteorites magnetic?
No: most meteorites contain iron-nickel metal and will attract a magnet, but many achondrites, including most Martian, lunar and Vesta meteorites, react only weakly or not at all. Plenty of magnetic Earth rocks are not meteorites.
A magnet is one of the most useful first checks, because the great majority of meteorites contain metal. Iron meteorites are almost entirely iron-nickel alloy and grab a magnet hard. Ordinary chondrites, the commonest meteorites to fall, contain scattered grains of metal and usually attract a magnet clearly. The H group, whose name stands for high iron, tends to pull more strongly than the L and LL groups, which contain less metal.
Some meteorites barely notice a magnet, though. Achondrites are stony meteorites that melted inside their parent bodies, so most of their metal sank away to form a core. Eucrites, howardites and diogenites from the asteroid Vesta, lunar meteorites and Martian meteorites often contain only tiny amounts of metal. They may show a faint pull or none. Carbonaceous chondrites vary: some contain little metal but enough of the magnetic iron oxide magnetite to react weakly.
To catch weak attraction, hang a small strong magnet on a thread and bring the stone close; a slight swing is easier to see than a feeble tug. Be careful with precious specimens, though. Strong magnets can overprint the faint natural magnetism that scientists study in meteorites, so experts ask that fresh falls are kept away from them.
The test also works only one way. Many Earth materials are strongly magnetic, including magnetite, some basalts, iron-rich slag from old furnaces, and scraps of manufactured iron and steel. A magnetic stone is therefore not proof of a meteorite, and a non-magnetic one is not automatically ruled out. Treat the magnet as one clue among several, alongside weight, crust and the look of the inside.