When I was a kid we used to drag magnets around in the dirt and collect "iron filings". Are they pure iron, or something else?

  • 3
    $\begingroup$ How in the world would anyone be able to know? There are many different sorts of dirt out there, after all. $\endgroup$ Aug 22, 2020 at 21:41
  • 1
    $\begingroup$ I’m voting to close this question because we just don't know. $\endgroup$ Aug 22, 2020 at 22:10
  • 1
    $\begingroup$ Metallic iron deposits are exceptionally rare in the natural environment. The filings were almost certainly not iron, unless they were scraps or powders from human-based industrial operations. $\endgroup$
    – Curt F.
    Aug 23, 2020 at 0:56
  • $\begingroup$ The earth surface is littered* with rust particles, mostly from human sources. $\ce{Fe2O3}$ is magnetic. $\endgroup$
    – Karl
    Aug 23, 2020 at 6:46

1 Answer 1


More likely they were iron oxides. In moist soil ,iron/steel filings would not last more than a few weeks before turning to oxides. Now the "oxides" are not simply Fe O, Fe 2 O 3, Fe 3 O 4 , they are also hydrates, hydroxides ,etc.

  • $\begingroup$ Then again, not all oxides and hydroxides are magnetic. $\endgroup$ Aug 22, 2020 at 21:51
  • $\begingroup$ Agreed, i type slow and did not put in that qualification. $\endgroup$ Aug 23, 2020 at 0:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.