Mineral (Iron Ore)

Ironstone concretion

Siderite or Limonite concretion (FeCO3 or FeO(OH)·nH2O)

Hematite

Iron(III) oxide (Fe2O3)

Ferruginous Breccia

Breccia with Iron-rich (Hematite/Goethite) Matrix

Weathered iron-rich rock, likely limonite/goethite-bearing laterite

Limonite–goethite aggregate, commonly approximated as hydrated iron oxides (FeO(OH)·nH₂O)

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Ironstone Concretion (Moqui Marble type)

Ironstone Concretion (Fe2O3 with SiO2 core)

Iron Ore (Hematite/Magnetite mixture)

Ferrous Oxide (Fe2O3 / Fe3O4)

Ironstone Matrix with Jasper / Chert

Ferruginous Chert / Limonitic Jasper (SiO2 with Fe-oxides)

Ironstone Nodule / Limonite Concretion

Iron-rich sedimentary concretion (FeO(OH)·nH2O / Fe2O3)

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Ironstone Concretion (Limonite/Goethite)

Iron oxide concretion (contains FeO(OH)·nH2O)

Pyrite in Matrix (likely Quartz or Coal)

Iron Sulfide (FeS2)

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Hematite / Ironstone

Iron Oxide (Fe2O3)

Ironstone Concretion (Moqui Marble)

Ferruginous Concretion (Fe2O3 / FeO(OH))

Ferruginous Quartz

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Moss Agate and Hematite

Silica (SiO2) with fibrous inclusions of Manganese or Iron; Hematite (Fe2O3)

Botryoidal Hematite (Kidney Ore)

Hematite (Fe2O3)

Iron-rich weathered rock (probable laterite or ironstone)

Goethite–hematite-bearing ironstone; approximately FeO(OH) and Fe₂O₃

Quartz with Chalcopyrite

Silicon Dioxide (SiO2) with Copper Iron Sulfide (CuFeS2)

Ironstone Concretion

Ironstone (Siderite/Goethite/Hematite matrix)

Hematite Concretion

Iron oxide (Fe2O3) in concretionary form

Yellow Ochre / Limonite

Limonite (Hydrated Iron(III) Oxide-Hydroxide, FeO(OH)·nH2O)

Specular Hematite

Specularite (Iron Oxide, Fe2O3)

Red Jasper and Hematite

Silicon Dioxide (SiO2) and Iron Oxide (Fe2O3)

Weathered iron-rich rock, possibly laterite or limonite-bearing sandstone

Laterite/limonite-rich material; commonly dominated by goethite (FeO(OH)) and hydrated iron oxides

Hematite (Iron Ore)

Hematite (alpha-Fe2O3)

Pyrite

Iron Disulfide (FeS2)

Vesicular Basalt with Magnetite/Hematite

Mafic Extrusive Igneous Rock (primarily Plagioclase and Pyroxene)

Hematite

Iron(III) oxide (Fe2O3)

Iron-rich weathered rock, likely limonite/goethite-bearing laterite

Limonite (variable hydrated iron oxides; chiefly goethite, α-FeO(OH))

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Pyrite

Iron Sulfide (FeS2)

Pyrite with Iron Oxides (Fool's Gold in Matrix)

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Banded Iron Formation (BIF) / Chert

Banded Iron Formation (SiO2 with Fe2O3 / Fe3O4)

Red Hematite

Iron(III) Oxide (Fe2O3)

Banded Iron Formation (BIF)

Banded Iron Formation (predominantly Hematite Fe2O3 and Magnetite Fe3O4 with Chert SiO2)