Mineral (Iron Ore)

Specular Hematite

Hematite (Fe2O3)

Hematite

Hematite (Fe2O3)

Hematite Ball

Iron(III) oxide (Fe2O3)

Peacock Ore (Bornite/Chalcopyrite)

Bornite (Cu5FeS4) or Chalcopyrite (CuFeS2)

Ironstone / Hematite

Iron(III) oxide (Fe2O3)

Iron-rich slag or ironstone; appearance is not diagnostic

Likely iron-oxide-rich material (hematite, Fe₂O₃, and/or magnetite, Fe₃O₄); possibly smelting slag

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Specular hematite (likely iron-rich ore)

Hematite, Fe₂O₃; possibly magnetite-bearing

Bauxite

Bauxite (Al(OH)3, AlO(OH))

Banded Iron Formation (BIF) or similar banded sedimentary rock

Banded Iron Formation

Hematite (or Magnetite iron ore gravel)

Hematite (Fe2O3) / Magnetite (Fe3O4)

Specular Hematite (Specularite)

Hematite (Fe2O3)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Hematite

Hematite (Α-Fe2O3)

Copper-bearing rock, likely bornite/chalcopyrite in iron-rich matrix

Chalcopyrite (CuFeS₂) and/or bornite (Cu₅FeS₄) in limonite/goethite matrix

Limonite (Oxidized Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Magnetite or Hematite Nodule

Iron Oxide (Fe3O4 or Fe2O3)

Limonite (Iron Ore)

Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)

Limonite (Iron Stone/Goethite)

Limonite (mixture of hydrated iron oxides, primarily Goethite: α-FeO(OH))

Ironstone concretion (possibly limonite/goethite-bearing)

Limonite, a mixture of hydrated iron oxides, commonly including goethite (α-FeO(OH))

Polished dark mineral fragments, likely hematite or magnetite

Hematite (Fe₂O₃) or magnetite (Fe₃O₄)

Limonite Concretion

Goethite-rich Concretion (FeO(OH))

Hematite

Iron(III) oxide (Fe2O3)

Limonite (Ironstone)

Limonite (FeOO·nH2O)

Limonite (Ironstone Concretion)

Limonite (FeO(OH)·nH2O)

Ironstone pebble (likely limonite/goethite-rich)

Limonite, a mixture of hydrated iron oxides; commonly dominated by goethite (α-FeO(OH))

Iron-rich breccia (likely hematite–goethite breccia)

Hematite (Fe₂O₃) and goethite (FeO(OH)) in a silicified or iron-cemented breccia

Limonite (Iron Ore)

Hydrous ferric oxides (FeO(OH)·nH2O)

Tumbled dark metallic mineral specimen, possibly hematite or magnetite

Hematite (Fe₂O₃) or magnetite (Fe₃O₄); visual identification is uncertain

Limonite after Pyrite (Prophecy Stone or Ironstone Concretion)

Goethite/Limonite pseudomorph after Pyrite/Marcasite (FeO(OH)·nH2O)

Limonite (Iron Ore)

Goethite and related iron hydroxides (FeO(OH)·nH2O)

Limonite (Iron Ore)

Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)

Yellow Ochre / Limonite

Limonite (FeO(OH)·nH2O)

Banded Iron Formation (Fragment)

Banded Iron Formation (BIF)

Hematite Mineral Ore

Iron(III) oxide (Fe2O3)

Iron-rich banded rock, likely goethite/limonite-rich ironstone

Goethite (α-FeO(OH)) and/or limonite with iron-oxide-stained silica or clay; exact identification requires testing

Specular Hematite

Hematite (Fe2O3)

Iron-rich metamorphic rock, likely hematite-bearing schist or ironstone

Hematite/goethite-rich quartz–mica schist or banded ironstone; Fe₂O₃ and FeO(OH) are probable major iron minerals

Likely iron-rich laterite or limonite/goethite nodule

Hydrated iron oxides, chiefly limonite (FeO(OH)·nH₂O) and/or goethite (FeO(OH))

Ironstone Concretion

Ironstone (Limonite/Goethite/Hematite mixture)

Ironstone (likely Limonite or Goethite nodule)

Hydrothermally altered Ferric Hydroxide (FeO(OH)·nH2O)

Ironstone (with Limonite/Goethite)

Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O and Hematite Fe2O3)