Mineral, Specifically An Iron Ore

Iron Ore / Ironstone Concretion

Mixture of iron oxide/hydroxide minerals, likely some combination of Hematite (Fe2O3), Goethite (α-FeOOH), and Limonite (a general term for hydrated iron oxides of variable composition) or potentially Bauxite (a mixture of aluminum hydroxides, often with iron oxides, (Al(OH)3) and FeO(OH)). The visual characteristics strongly suggest iron-rich material.

Sandstone (specifically an Iron-Concretion)

Arenite with Iron Oxide (Limonite/Goethite) cementation

Ferruginous Sandstone

Sandstone (rich in iron oxides/hydroxides)

Limonite Pseudomorph after Pyrite

Limonite (Hydrous iron oxides, FeO(OH)·nH2O) replacing Pyrite (FeS2)

Hematite

Iron(III) oxide (Fe2O3)

Botryoidal Hematite (Iron Stone Conglomerate)

Hematite (Fe2O3) in sedimentary matrix

Specular Hematite (Specularite)

Iron(III) oxide (Fe2O3)

Pyrite

Iron Sulfide (FeS2)

Specular Hematite (Specularite)

Hematite (Iron(III) oxide) - Fe2O3

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Banded Iron Formation (BIF) / Tiger Iron

Ferruginous Chert (primarily Quartz [SiO2] and Hematite/Magnetite [Fe2O3/Fe3O4])

Ironstone Concretion (Moqui Marble)

Iron-oxide Concretion (Hydrated ferric oxide, Fe2O3·nH2O)

Ferrocoke or Slag

Anthropogenic pyrometallurgical residue

Ferruginous Sandstone

Sandstone with iron oxide (Hematite/Limonite) cement

Limonite/Goethite Gossan

FeO(OH)·nH2O (Hydrated iron oxide)

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Quartzite (specifically an iron-stained or Carnelian-colored variety)

Silicon Dioxide (SiO2) with iron oxide inclusions

Limonite with Hematite

Limonite (FeO(OH)·nH2O) and Hematite (Fe2O3)

Ironstone Concretion / Limonite Node

Goethite and Limonite (FeO(OH) nH2O)

Limonite

Limonite (FeOO·nH2O)

Gossan (Iron Hat)

Limonitic Gossan (predominantly FeO(OH)·nH2O)

Limonite (Iron Ore)

Limonite (Hydrous iron(III) oxide-hydroxide mixture, primarily FeO(OH)·nH2O)

Goethite

Goethite (FeO(OH))

Limonite (Iron Ore)

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

Botryoidal Goethite

Goethite (α-Fe3+O(OH))

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Jasper (Green Jasper/Chert)

Silicon Dioxide (SiO2)

Aquamarine

Beryl (Be3Al2Si6O18 with iron impurities)

Turquoise and Hematite

CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Fe2O3 (Hematite)

Gossan (Iron Hat)

Limonitic Gossan (Fe-oxide/hydroxide complex)

Basalt (Drill Core)

Mafic Volcanic Rock (Basalt)

Limonite (Ironstone)

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

Limonite (with goethite)

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

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Limonite Concretion (Ironstone)

Limonite (FeO(OH)·nH2O) / Goethite

Aragonite Star Cluster

Aragonite (Calcium Carbonate - CaCO3)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Ironstone Concretion

Siderite or Hematite Concretion

Yellow Ocher / Limonite

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

Limonite (Iron Ore/Bog Iron)

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

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Gossan (Limonite/Goethite)

Hydrated iron oxides (primarily FeO(OH)·nH2O)