# How to identify magnetite

Canonical page: https://lithomap.app/resources/mineral-identification/magnetite
Last reviewed: September 17, 2026
Page purpose: Original LithoMap mineral identification reference for field observations, search systems, and language models.
Classification: Iron oxide mineral · Fe₃O₄

## Summary

Magnetite is a black iron oxide readily recognized by strong attraction to a magnet, black streak, relatively high density, and commonly octahedral or granular form.

## Quick identification clues

- Strongly magnetic
- Black streak
- Black metallic to submetallic luster
- Dense; crystals commonly octahedral

## Composition and classification

Magnetite contains both ferrous and ferric iron. Titanium and other elements can substitute, and intergrowths with related oxides may affect magnetic behavior.

## Appearance

Magnetite forms octahedral crystals, granular aggregates, massive layers, and disseminated grains. Fresh surfaces are black with metallic to dull luster.

Weathering can replace magnetite with hematite, maghemite, goethite, or mixtures, producing rusty surfaces and weaker magnetism.

## Identification tests

- Magnetism: Strong attraction to a hand magnet. The key field property; test several parts of mixed rock.
- Streak: Black. Separates magnetite from red-streaking hematite.
- Hardness: 5.5 to 6.5. Harder than many black oxides and most weathered coatings.
- Density: Noticeably heavy for size. Supports an iron-rich mineral but is not unique.

## Common lookalikes

- Hematite: Leaves a red-brown streak and is ordinarily much less magnetic.
- Ilmenite: Has a black streak but is usually only weakly magnetic unless altered or intergrown.
- Industrial slag: May be magnetic but commonly shows bubbles, glassy textures, or furnace context.

## Direct side-by-side comparisons

- Hematite vs. magnetite — https://lithomap.app/resources/mineral-identification/compare/hematite-vs-magnetite
- Ilmenite vs. magnetite — https://lithomap.app/resources/mineral-identification/compare/ilmenite-vs-magnetite

## Most relevant related guides

- Hematite — https://lithomap.app/resources/mineral-identification/hematite
- Ilmenite — https://lithomap.app/resources/mineral-identification/ilmenite
- Cassiterite — https://lithomap.app/resources/mineral-identification/cassiterite
- Galena — https://lithomap.app/resources/mineral-identification/galena

## Formation

Magnetite crystallizes from magma, develops during metamorphism, forms in hydrothermal systems, and accumulates as heavy grains in sediment.

It can occur as an accessory mineral or dominate iron-rich layers and ore bodies. Geological context determines significance.

## Occurrence and geologic setting

Magnetite occurs in many igneous and metamorphic rocks, iron formations, skarns, black sands, and some hydrothermal deposits.

Magnetic black sand may include magnetite with several other dense minerals. A magnet concentrates grains but does not identify every component.

## Uses and significance

Magnetite is a major iron ore and is used in dense media, pigments, magnetic materials, and specialized industrial applications.

## Field safety and limitations

- A magnetic rock is not automatically a meteorite.
- Keep strong magnets away from electronics and medical devices.
- Mine dumps and iron-rich dust can contain additional hazardous minerals.

## Authoritative sources

- Minerals and their physical properties — U.S. National Park Service: https://www.nps.gov/subjects/geology/minerals.htm
- Mohs Hardness Scale — U.S. National Park Service: https://www.nps.gov/articles/mohs-hardness-scale.htm
- Natural Gemstones: Mineral Gemstones — U.S. Geological Survey: https://pubs.usgs.gov/gip/gemstones/mineral.html

## Specimen photograph

- Image: https://lithomap.app/_delivery/identification/minerals/magnetite.webp
- Description: Black metallic magnetite crystal specimen
- Creator: Robert M. Lavinsky
- License: CC BY-SA 3.0 — https://creativecommons.org/licenses/by-sa/3.0/
- Source record: https://commons.wikimedia.org/wiki/File:Magnetite-118736.jpg

This reference supports preliminary field identification. It is not a laboratory determination, appraisal, hazard assessment, proof of origin, or statement of land ownership, legal access, or collecting permission.