Mineral (Iron Ore)

Ironstone Concretion (Limonite/Goethite)

Ironstone (primarily FeO(OH)·nH2O)

Pyrite

Iron Disulfide (FeS2)

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Magnetite

Magnetite (Fe3O4)

Magnetite (likely with weathered Limonite/Hematite)

Magnetite (Fe3O4) with iron oxide weathering

Tiger's Eye and Hematite

Quartz (SiO2) with Crocidolite inclusions and Hematite (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Gold-bearing Quartz and Pyrite

Auriferous Quartz (SiO2 + Au) with Pyrite (FeS2)

Iron-rich slag or limonite-bearing rock

Hydrated iron oxides, chiefly limonite/goethite (FeO(OH)·nH₂O); possibly industrial iron slag

Jasper (Iron-stained)

Jasper (Silicon Dioxide, SiO₂ with Iron inclusions)

Iron sulfide-rich ore, possibly pyrite-bearing gossan

Likely pyrite (FeS₂) with iron oxides/hydroxides and host rock; exact identification requires testing

Iron Ore (Goethite and Hematite)

Iron Oxyhydroxide (α-FeO(OH)) and Iron(III) oxide (Fe2O3)

Pyrite cluster in a sulfide-rich ore matrix

Pyrite, FeS₂, likely with pyrrhotite and/or chalcopyrite in matrix

Drill Core (Basalt or Andesite)

Volcanic porphyry (mafic to intermediate)

Pyrite (“fool’s gold”)

Pyrite, iron disulfide (FeS₂)

Ferruginous Conglomerate (or Iron-Rich Concrete/Slag)

Clastic Sedimentary (Silicon Dioxide/Iron Oxide matrix)

Likely weathered iron-rich rock or mineral fragment

Indeterminate; possibly limonite/goethite-rich material with quartz or feldspar

Limonite with Trace Fossils

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

Quartz with Hematite Inclusions

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3)

Banded Iron Formation (BIF) / Jasper

Banded Iron Formation (SiO2 with Fe2O3 / Fe3O4)

Banded Iron Formation

Banded Iron Formation (BIF)

Galena with Pyrite

Lead Sulfide (PbS) associated with Iron Sulfide (FeS2)

Ferruginous Quartzite (also known as Ironstone or Gossan)

Ferruginous Quartzite with Goethite/Hematite staining

Copper-bearing Quartz (with Malachite and Iron Oxides)

Quartz (SiO2) with Malachite (Cu2CO3(OH)2) and Hematite/Limonite (Fe2O3)

Banded Iron Formation

Banded Iron Formation (BIF)

Ironstone Concretion (Limonite/Goethite)

Goethite/Limonite concretion (FeO(OH)·nH2O)

Nobby Hematite (Iron Ore)

Hematite (Fe2O3)

Limonite (Iron Ore/Sandstone mixture)

Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix

Ironstone Concretion (Limonite/Goethite)

Iron-rich sedimentary rock (FeOx)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Pyrite (Fool's Gold) in Matrix

Iron Sulfide (FeS2)

Aquamarine

Beryl (Be3Al2Si6O18 with iron impurities)

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Hemimorphite or Red Quartz

SiO2 (Quartz) / Zn4Si2O7(OH)2·H2O (Hemimorphite)

Chrysocolla on Quartz with Iron Oxides

Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O)

Magnetite / Ironstone

Magnetite (Fe3O4)

Hematite

Ferric Oxide (Fe2O3)

Bauxite

Bauxite (Mixture of Al(OH)3, AlO(OH), and Fe2O3)

Quartz-rich metallic sulfide ore (probable pyrite-bearing rock)

Pyrite, FeS₂, in a quartz-rich host; exact identification is uncertain from the image

Banded Iron Formation (BIF)

Banded Iron Formation (Fe2O3 + SiO2)

Ironstone Concretion

Ironstone (primarily Siderite or Limonite)