Mineral, Specifically An Iron Ore

Limonite (Ironstone)

Limonite (FeOO·nH2O)

Spinosaurus Tooth

Spinosaurus aegyptiacus (fossilized in Hydroxyapatite)

Iron-rich breccia (likely hematite–goethite breccia)

Hematite (Fe₂O₃) and goethite (FeO(OH)) in a silicified or iron-cemented breccia

Limonite (Iron Ore)

Hydrous ferric oxides (FeO(OH)·nH2O)

Limonite (Ironstone Concretion)

Limonite (FeO(OH)·nH2O)

Ironstone pebble (likely limonite/goethite-rich)

Limonite, a mixture of hydrated iron oxides; commonly dominated by goethite (α-FeO(OH))

Ironstone (iron-oxide-rich rock)

Likely goethite/limonite-rich ironstone; exact identification requires closer examination

Yellow Jasper

Silicon Dioxide (SiO2)

Limonite (Iron Ore)

Goethite and related iron hydroxides (FeO(OH)·nH2O)

Limonite after Pyrite (Prophecy Stone or Ironstone Concretion)

Goethite/Limonite pseudomorph after Pyrite/Marcasite (FeO(OH)·nH2O)

Limonite (Iron Ore)

Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)

Yellow Ochre / Limonite

Limonite (FeO(OH)·nH2O)

Banded Iron Formation (Fragment)

Banded Iron Formation (BIF)

Mahogany Obsidian

Volcanic Glass (SiO2 + Fe2O3)

Carnelian (a variety of Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

Hematite Mineral Ore

Iron(III) oxide (Fe2O3)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2) with Limonite/Goethite

Yellow Jasper / Chert

Silicon Dioxide (SiO2) with Goethite or Limonite inclusions

Sandstone with Iron Staining

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

Iron-rich banded rock, likely goethite/limonite-rich ironstone

Goethite (α-FeO(OH)) and/or limonite with iron-oxide-stained silica or clay; exact identification requires testing

Specular Hematite

Hematite (Fe2O3)

Iron-rich metamorphic rock, likely hematite-bearing schist or ironstone

Hematite/goethite-rich quartz–mica schist or banded ironstone; Fe₂O₃ and FeO(OH) are probable major iron minerals

Likely iron-rich laterite or limonite/goethite nodule

Hydrated iron oxides, chiefly limonite (FeO(OH)·nH₂O) and/or goethite (FeO(OH))

Ironstone Concretion

Ironstone (Limonite/Goethite/Hematite mixture)

Ironstone (likely Limonite or Goethite nodule)

Hydrothermally altered Ferric Hydroxide (FeO(OH)·nH2O)

Weathered iron-rich rock (possibly ironstone)

Likely ferruginous sandstone or ironstone; exact identification requires examination

Ironstone (with Limonite/Goethite)

Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O and Hematite Fe2O3)

Yellow Ochre / Limonite

Hydrated ferric oxide (FeO(OH)·nH2O)

African Turquoise

Jasper / Quartz matrix (Trade name: African Turquoise, chemically a form of microcrystalline quartz with various mineral inclusions)

Hematite

Hematite (Iron(III) oxide, Fe2O3)

Likely hematite-rich ironstone or metallic mineral fragment

Hematite (Fe₂O₃), possibly with magnetite (Fe₃O₄) or metallic iron

Sandstone (specifically Picture Sandstone or Wonderstone)

Arenite (composed primarily of SiO2)

Rose Quartz

Silicon dioxide (SiO2) with traces of titanium, iron, or manganese

Magnetite

Magnetite (Fe3O4)

Limonite Concretion

FeO(OH)qnH2O (Hydrated iron(III) oxide-hydroxide mixture)

Picture Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Limonite (Yellow Ochre)

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

Red Jasper

Silicon dioxide (SiO2) with hematite (Fe2O3) inclusions

Sandstone (with Possible Iron Staining/Crust)

Arenite (SiO2 based)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Orange Calcite

Calcium Carbonate (CaCO3)

Orange Calcite

Calcium Carbonate (CaCO3)