Mineral, Specifically An Iron Ore

Banded Iron Formation (BIF)

Banded Iron Formation

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Red Granite

Phaneritic Felsic Intrusive Igneous Rock (primarily K-feldspar, Quartz, and Biotite)

Chert (Iron-stained)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (Jasper)

Chert / Microcrystalline Quartz (SiO2)

Banded Iron Formation (BIF) / Tiger Iron

Banded Iron Formation containing Hematite (Fe2O3) and Magnetite (Fe3O4)

Beryl (Aquamarine) in Matrix

Beryllium aluminum silicate (Be3Al2(SiO3)6)

Iron Slag

Anthropogenic Vitreous Silicate (Byproduct of Smelting)

Tree Agate

Silicon Dioxide (SiO2) with Chlorite inclusions

Silver (Native Element)

Silver (Ag) in an alloy of 90% Silver and 10% Copper

Chert (specifically Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Ferrochrome Slag

Anthropogenic slag (Fe-Cr alloy waste)

Zebra Jasper

Silicon Dioxide (SiO2) with impurities; typically a form of Chalcedony/Microcrystalline Quartz

Tumbled Moonstone

Feldspar (Orthoclase/Albite), KAlSi3O8

Quartz with Pyrite

Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)

Magnetite

Magnetite (Iron(II,III) oxide, Fe3O4)

Red Jasper (Opaque Chalcedony)

Silicon Dioxide (SiO2) with Hematite inclusions

Marble

Recrystallized Carbonate Rock (CaCO3)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Red Jasper (Siltstone/Quartz variety)

Silicon Dioxide (SiO2) with Hematite impurities

Red Jasper

Jasper (Silica with Hematite impurities), SiO2

Ferruginous Conglomerate

Conglomerate with Iron-Oxide Matrix (SiO2 + Fe2O3/FeO(OH))

Red Jasper

Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions

Jasper (specifically Polychrome or Desert Jasper)

Silicon Dioxide (SiO2) with impurities

Limonite stained Sandstone

Sedimentary rock with Goethite/Limonite (FeO(OH)·nH2O)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Banded Iron Formation (BIF) / Tiger Iron variety

Banded Iron Formation (composed primarily of Magnetite Fe3O4, Hematite Fe2O3, and Chert/Quartz SiO2)

Ocean Jasper (Orbicular Jasper)

Silicon Dioxide (SiO2) with iron and magnesium inclusions

Ferruginous Sandstone (Ironstone Nodules)

Ferruginous Sandstone with Limonite/Goethite coating (Fe2O3·H2O)

Rose Quartz

Silicon Dioxide (SiO2) with trace elements of Titanium, Iron, or Manganese

Banded Iron Formation (BIF) with Quartz

Banded Iron Formation, often composed of alternating layers of hematite (Fe2O3) or magnetite (Fe3O4) and chert (microcrystalline quartz, SiO2)

Conglomerate (Puddingstone)

Conglomerate (specifically, clastic sedimentary rock)

Ironstone Concretion (Limonite/Goethite)

Ferruginous Sandstone / Ironstone (FeO(OH)·nH2O)

Rhodonite

Rhodonite (Manganese Iron Magnesium Calcium Silicate - (Mn,Fe,Mg,Ca)SiO3)

Limestone (specifically Travertine or Tufa)

Calcium Carbonate (CaCO3)

Olivine (Peridot when gem-quality)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Red Jasper

Silicon dioxide (SiO2) with iron oxide (Hematite) inclusions

Ferruginous Sandstone (Ironstone Conglomerate fragments)

Ferruginous clastic sedimentary rock (SiO2 cemented by Fe2O3)

Banded Iron Formation (BIF)

Banded Iron Formation (composed primarily of Hematite [Fe2O3], Magnetite [Fe3O4], and Chert [SiO2])

Pyrite in Quartz

Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)

Moss Agate

Silicon Dioxide with inclusions (SiO2 + impurities)

Ferruginous Sandstone

Arenite with Hematite/Limonite cement (SiO2 + Fe2O3)