Magnetite — Magnetite
Magnetite Archaeodontosaurus, Wikimedia Commons, CC BY SA 3.0

Mineral · Spinel group

Magnetite

Fe2+Fe3+2O4

Magnetite is the black, strongly magnetic iron oxide, crystallising as octahedra at Bolivia's Cerro Huanaquino, in Utah's Iron Springs district and in Alpine chlorite schists; lodestone is naturally magnetised magnetite. A magnet and a black streak settle the identification. It is common and inexpensive.

FormulaFe2+Fe3+2O4
IMA statusgrandfathered
Crystal systemCubic
Mohs hardness5.5–6.5
GroupSpinel group
Type localityNone (known since antiquity)
StreakBlack
Specific gravity5.2
Reference listIMA List of Minerals (RRUFF) — verify formula and status against the current list

Elsewhere

Cite this article

Stratum Study. "Magnetite" (Mineral). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/minerals/magnetite. Accessed 2026-09-20.

@misc{stratum-magnetite,
  title        = {Magnetite},
  author       = {{Stratum Study}},
  howpublished = {\url{https://stratum.black/study/minerals/magnetite}},
  year         = {2026},
  note         = {Mineral article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, wikidata, commons. Accessed 2026-09-20.}
}

Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.

Sources for this article: Stratum editorial (Stratum editorial);Wikidata (CC0);Wikimedia Commons (CC-BY-4.0). As of 2026-09-19; Study pack 2026.09. Data reproduced under the licences shown; text in Stratum's own words unless a section names its source.

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