Sedimentary (Physico Chemical Precipitate)

Banded iron formation fragment (iron-rich chert/jasper)

Banded iron formation; microcrystalline quartz (SiO₂) with hematite/magnetite and iron oxides

Banded iron formation (ironstone), likely hematite–magnetite jasper

Banded iron formation (BIF), chiefly Fe₂O₃ hematite, Fe₃O₄ magnetite, and SiO₂ quartz/chert

Yellow calcite fragment

Calcite (CaCO₃), likely honey/yellow calcite

Coquina Limestone (Fossiliferous Limestone)

Calcareous bioclastic sedimentary rock (CaCO3)

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Banded iron formation pebble (likely jasper-rich ironstone)

Banded iron formation (BIF), composed mainly of hematite/magnetite and microcrystalline quartz (chert/jasper)

Limestone

Calcium Carbonate (CaCO3)

Barite Rose on Marcasite

Barium Sulfate (BaSO4) on Iron Sulfide (FeS2)

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Orange calcite

Calcite (CaCO₃)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Hematite/Limonite

Pink Zebra Jasper

Microcrystalline Quartz (SiO2)

Honey calcite crystal

Calcite (calcium carbonate, CaCO₃)

Rounded ironstone concretion

Iron-rich sedimentary concretion, commonly composed of goethite and/or hematite cementing sand or clay

Hematite

Iron(III) oxide (Fe2O3)

Quartz Geode

Silicon Dioxide (SiO2) in a sedimentary host

Moqui Marble (Concretion)

Iron Oxide Concretion

Limonite (Limonitic Sandstone)

Hydrated Iron(III) Oxide-Hydroxide ($FeO(OH)·nH_2O$)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Weathered ironstone pebble (likely ferruginous concretion)

Iron-oxide-cemented concretion, commonly hematite (Fe₂O₃) and/or goethite (FeO(OH))

Ironstone concretion (possibly pyrite-bearing)

Iron-rich sedimentary concretion, likely composed of goethite/limonite with possible pyrite

Banded iron formation (ironstone)

BIF; hematite–magnetite–quartz/chert assemblage

Calcite

Calcite (CaCO₃), likely crystalline limestone or marble fragment

Pale limestone

Limestone, predominantly calcite (CaCO₃)

Ironstone concretion

Iron-oxide-cemented sediment, chiefly goethite (α-FeO(OH)) and/or hematite (Fe₂O₃)

Possible iron-oxide concretion with a dark mineral cap

Iron-oxide–cemented sedimentary concretion; exact composition cannot be determined from the image

Agate

Agate (Silicon Dioxide - SiO2)

Banded iron formation (ironstone), possibly hematite–magnetite-rich

Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and chert/microcrystalline quartz (SiO₂)

Banded iron formation fragment (polished ironstone)

Banded iron formation; hematite/magnetite-rich chert, commonly approximated as Fe₂O₃–Fe₃O₄ with SiO₂

Banded iron formation fragment (likely hematite–magnetite-rich ironstone)

Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica/chert (SiO₂)

Weathered iron-rich chert or jasper

Microcrystalline quartz (SiO₂), variably stained by iron oxides

Honey-brown calcite crystal cluster

Calcite (CaCO₃), likely dogtooth or scalenohedral calcite

Chalky limestone fragment

Micritic limestone, chiefly calcite (CaCO₃)

Shale with Quartz Veins

Fissile Sedimentary Rock (SiO2)

Red sandstone or iron-stained chert

Likely quartz-rich sandstone (SiO₂) or microcrystalline quartz/chert with hematite

Blue Calcite

Calcium Carbonate (CaCO3)

Likely red jasper or iron-rich chert

Microcrystalline quartz (SiO₂) colored by hematite/goethite

Banded chert pebble

Chert (microcrystalline quartz, SiO₂), likely ribbon-banded chert

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Banded Sandstone (Liesegang Rings)

Sedimentary Arenite (SiO2 with FeO/Fe2O3 impurities)

Honey-colored calcite

Calcite (calcium carbonate, CaCO₃), likely rough or partly polished

Fossiliferous Limestone

Sedimentary rock containing Indeterminate Fossil remains (likely Crinoid stem or Bryozoan fragment)