Why the test works
Minerals differ in magnetic susceptibility because of their composition and atomic structure. Magnetite can respond strongly, while many iron-bearing minerals are only weakly attracted or appear nonmagnetic in a hand test.
A small amount of magnetite can make an otherwise nonmagnetic rock respond. Testing several locations helps detect mixtures instead of assigning the response to every grain.
How to perform the test
- 1
Clean and isolate
Remove loose steel fragments, soil, and obvious manufactured debris. Place small grains on white paper.
- 2
Approach without contact
Bring the magnet slowly toward the sample. Movement before contact demonstrates attraction more clearly than material merely sticking to the magnet after touch.
- 3
Compare several points
Test different grains, matrix, coatings, and fresh surfaces. Note whether the response is uniform or localized.
- 4
Grade the response
Record strong, weak, uncertain, or none using the same magnet and distance. Do not convert a hand test into a numerical susceptibility.
- 5
Check remanence separately
If relevant, suspend the specimen or use a compass at a safe distance from electronics. Attraction to a magnet and acting as a permanent magnet are different observations.
How to read the result
Strong movement toward a small magnet before contact
Supports abundant strongly magnetic material such as magnetite.
Weak or localized attraction
May reflect sparse magnetite, an intergrowth, weathering products, or a weakly magnetic mineral. Map the responding spots.
No obvious response
Rules out only a strong response under the test conditions; it does not show that iron or weak magnetic susceptibility is absent.
Specimen influences a compass or aligns when suspended
Possible remanent magnetization. Keep away from navigation and electronic equipment and confirm with controlled methods.
Examples from the LithoMap guide library
Magnetite
Commonly shows strong attraction and a black streak.
Ilmenite
Often weaker and variable; intergrowths with magnetite complicate hand tests.
Hematite
Usually weak or apparently nonmagnetic in a simple test despite its iron content.
Basalt
May respond because of iron-bearing oxide grains, but magnetism does not identify the whole rock.
Common mistakes
- Touching the sample first and mistaking adhesion or trapped grains for attraction
- Using different magnets or distances without recording the change
- Assuming every dark magnetic specimen is magnetite or a meteorite
- Ignoring steel filings, drilling fragments, or magnetic dirt
- Treating a localized magnetic grain as the composition of the entire rock
Test safely
- Keep strong magnets away from pacemakers and other medical devices according to manufacturer guidance.
- Protect phones, magnetic cards, compasses, watches, and sensitive electronics.
- Bag the magnet so attached grains can be removed without scraping or creating dust.
- Magnetism does not establish that a specimen is safe to handle, valuable, extraterrestrial, or lawfully collectible.
This method supports preliminary field identification. It is not laboratory confirmation, appraisal, hazard clearance, proof of origin, or permission to collect or alter a specimen.
Frequently asked questions
Does a magnetic rock mean I found a meteorite?
No. Many ordinary Earth rocks contain magnetite or other magnetic grains. Meteorite evaluation requires texture, density, chemistry, and expert evidence beyond a magnet.
Why is only one part of my rock magnetic?
Rocks are mixtures. A vein, grain cluster, surface contamination, or altered zone may contain the magnetic material while the rest does not.
Is hematite magnetic?
Hematite is much less responsive than magnetite in ordinary hand tests. Natural mixtures, heating history, and magnetite inclusions can change the observed response.
Authoritative sources
LithoMap wrote this guide in original language using the physical-property standards and safety information supported by these sources.
- Geology Lesson 2: Global Building Blocks U.S. National Park Service
- Magnetic susceptibilities of minerals U.S. Geological Survey
- Minerals and their physical properties U.S. National Park Service
Editorial review: September 18, 2026.