Mineral (Iron Ore)

Hematite

Iron(III) oxide (Fe2O3)

Chalcopyrite in Quartz (Gossan/Iron Hat)

CuFeS2 (Chalcopyrite) with SiO2 (Quartz)

Limonite / Goethite (Ironstone Nodule)

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

Raw botryoidal goethite/limonite specimen

Goethite (α-FeO(OH)), commonly mixed with limonite (hydrated iron oxides)

Limonite / Brown Iron Ore

Hydrous Iron Oxide (FeO(OH)·nH2O)

Hematite

Iron(III) oxide (Fe2O3)

Ferruginous Quartz

Quartz (Silicon Dioxide) with Iron Inclusion, SiO2

Orange mineral fragment, possibly iron oxide or carnelian

Uncertain; candidates include hematite/goethite (Fe₂O₃/FeO(OH)) or orange chalcedony (SiO₂)

Limonite (Hydrated Iron Oxide / Bog Iron)

FeO(OH)·nH2O

Hematite

Iron(III) oxide (Fe2O3)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Limonite/goethite-rich ironstone concretion (probable)

Goethite–limonite, chiefly FeO(OH)·nH₂O, possibly with hematite and manganese oxides

Limonite with Ironstone

Limonite (hydrated iron(III) oxide-hydroxides), FeO(OH)·nH2O

Gold Ore

Native Gold (Au) in Matrix

Likely hematite-bearing ironstone

Hematite (Fe₂O₃), possibly mixed with other iron oxides and host rock

Iron-rich concretion or weathered ironstone

Limonite/goethite-rich ironstone; commonly hydrated iron oxides (FeO(OH)·nH₂O)

Limonite (Iron Ore)

Hydrated ferric oxide (FeO(OH)·nH2O)

Limonite Geode / Ironstone Concretion

Hydrated Iron Oxide (FeO(OH)·nH2O)

Limonite

FeO(OH)·nH2O

Polished hematite sphere

Hematite (Fe₂O₃), likely a polished specular or massive variety

Copper Ore Specimen with Malachite

Cuprite, Malachite, and Limonite matrix

Limonite Concretion

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

Weathered iron-rich rock fragment

Likely limonite/goethite with hematite and iron-bearing silicates; exact identification requires testing

Hematite

Hematite (Fe2O3)

Specular Hematite (Specularite)

Hematite (Alpha-Fe2O3)

Magnetite / Ironstone Pebble

Magnetite (Fe3O4)

Yellow Ochre

Goethite-rich clay (Hydrated Iron Oxide: FeO(OH)·nH₂O)

Likely iron-rich sulfide ore (possibly sphalerite with oxidized iron minerals)

Appearance may indicate sphalerite (ZnS) with limonite/goethite staining; identification from the image is uncertain.

Bog Iron (Limonite)

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

Iron-rich rock or weathered metallic mineral specimen

Uncertain; possibly limonite/goethite with iron oxides, or a metallic sulfide such as pyrite/chalcopyrite

Ironstone Concretion (Coprolite-like)

Goethite/Hematite Siderite Spheroid (FeCO3 or FeO(OH))

Pyrite or Chalcopyrite

Iron sulfide (FeS2) or Copper iron sulfide (CuFeS2)

Limonite (Yellow Ochre)

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

Small polished metallic mineral specimen

Indeterminate from image; possibly galena or hematite

Weathered iron-rich rock fragment

Likely limonite/goethite-bearing ferruginous rock; exact identification requires testing

Specular Hematite (Specularite) in Matrix

Specularite (Fe2O3)

Limonite (Ironstone Concretion)

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

Chalcopyrite

Copper iron sulfide (CuFeS2)

Ironstone (iron-oxide-rich rock)

Ferruginous sandstone or ironstone; likely composed chiefly of goethite and/or limonite, with quartz and clay

Likely brown ironstone or limonite-rich rock fragment

Ironstone, chiefly iron oxides/hydroxides such as goethite (α-FeO(OH)) and limonite

Tumbled iron-rich stone, likely hematite-bearing rock

Hematite (Fe₂O₃), possibly mixed with magnetite/goethite and host rock

Goethite (Iron Ore)

Goethite (FeO(OH))