Mineral (Iron Ore)

Limonite (Iron Ore)

Hydrous ferric oxides (FeO(OH)·nH2O)

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Hematite (specular hematite)

Hematite, α-Fe₂O₃ (iron(III) oxide)

Specular Hematite Geode/Nodule

Specularite (Polycrystalline Hematite), Fe2O3

Tumbled hematite (likely hematite-rich ironstone)

Hematite, Fe₂O₃; possibly mixed with magnetite or goethite

Goethite/Limonite Iron Ore Node

Goethite (FeO(OH)) or Limonite (mixture of hydrated iron oxides)

Hematite

Hematite (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Limonite (Iron Ore)

Hydrated ferric oxide (FeO(OH)·nH2O)

Bauxite

Bauxite (mixture of Hydrous Aluminum Oxides)

Chalcopyrite (Peacock Ore)

Copper Iron Sulfide (CuFeS2)

Limonite-stained ironstone, possibly goethite

Goethite/limonite (FeO(OH) and hydrated iron oxides), identification tentative

Specularite in Quartz

Specular Hematite (Fe2O3) in Quartz (SiO2)

Banded iron formation fragment (likely hematite–magnetite ironstone)

BIF; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica as microcrystalline quartz (SiO₂)

Ironstone Concretion

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

Yellow Ochre (Limonite)

Limonite (FeO(OH)wH2O)

Iron (Hematite variety)

Iron (Fe) / Hematite (Fe2O3)

Likely pyrite-bearing rock fragment

Pyrite (FeS₂), possibly in a weathered host rock; identification is uncertain from the image

Weathered iron-rich rock, likely limonite/goethite-bearing basalt or ironstone

Limonite (hydrated iron oxides; chiefly goethite, FeO(OH)) with probable silicate host rock

Limonite

Hydrous Iron Oxide (often Goethite FeO(OH), Lepidocrocite γ-FeO(OH), and other amorphous iron oxyhydroxides)

Limonite Concretion

Limonite (FeO·nH2O)

Ironstone (Limonite/Hematite concretion)

Ferruginous Siltstone / Goethite (FeO(OH))

Pyrite (likely)

Pyrite, FeS₂

Hematite

Iron(III) oxide (Fe2O3)

Banded iron formation (iron-rich jasper/chert)

Banded iron formation, chiefly quartz (SiO₂) with hematite, magnetite, and/or goethite (Fe oxides/hydroxides)

Hematite (likely Botryoidal or Specularite variant)

Iron(III) oxide (Fe2O3)

Limonite (Iron Stone/Gossen)

Limonite (FeO(OH)·nH2O)

Lake Superior Agate

Silicon Dioxide (SiO2) - variety: banded chalcedony quartzite

Magnetite / Iron-Rich Basalt

Magnetite bearing Mafic Rock (Fe3O4)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Hematite

Iron(III) oxide (Fe2O3)

Iron-rich quartz rock, possibly hematite/goethite-bearing quartz

Quartz (SiO₂) with iron oxides/hydroxides, chiefly hematite (Fe₂O₃) and goethite (FeO(OH))

Yellow Ochre / Limonite

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

Weathered iron-rich rock (probable limonite/goethite)

Limonite: hydrated iron oxides, chiefly goethite (FeO(OH)) and hematite (Fe₂O₃)

Iron-oxide-rich breccia or weathered ironstone

Hematite–goethite ironstone, likely brecciated and quartz-bearing

Gossan (with secondary copper minerals)

Iron-rich oxidized rock cap (Limonite/Goethite with Malachite/Chrysocolla inclusions)

Chalcopyrite

Copper iron sulfide (CuFeS2)

Bauxite

Aluminium ore (Hydrated aluminium oxides AlOx(OH)3-2x)

Chalcopyrite (Peacock Ore)

Copper Iron Sulfide (CuFeS2)

Ferruginous Sandstone

Sandstone (arenite) with Limonite/Goethite cement

Limonite Geode (Ironstone Concretion)

FeO(OH)·nH2O (Hydrated Iron Oxide)