Sedimentary (Chemically Precipitated) Or Metamorphic

Magnetite Ore

Magnetite (Fe3O4)

Banded iron formation fragment (polished ironstone)

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

Aragonite (Onyx Marble)

Calcium Carbonate (CaCO3), Orthorhombic crystal system

Quartzite

Metamorphic Quartzite (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

Limestone Pebble

Calcite-rich Sedimentary Rock (CaCO3)

Quartz-rich iron-stained rock, likely quartzite or quartz vein material

Quartz (SiO₂), with iron oxides/hydroxides such as hematite and goethite

Sandstone with Liesegang Rings

Quartzose Sandstone with Iron Oxide Precipitation

Small quartz-rich pebble or rock fragment

Quartz (silicon dioxide, SiO₂), possibly with iron-oxide staining or host-rock inclusions

Raw Calcite

Calcium Carbonate (CaCO3)

Calcite

Calcium Carbonate (CaCO3)

Ironstone pebble (likely limonite/goethite-rich)

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

Quartz with Host Rock

SiO2 (Quartz) with fine-grained Matrix

Banded Iron Formation (BIF)

Banded Iron Formation (Taconite/Itabirite)

Oolitic Chert

Silicon Dioxide (SiO2) with oolitic texture

Blue Calcite

Calcium Carbonate (CaCO3)

Honey Calcite

Calcium Carbonate (CaCO3)

Polished banded ironstone pebble

Banded iron formation (BIF), chiefly hematite/magnetite and quartz

Banded ironstone pebble

Banded iron formation (BIF), chiefly quartz/chert and iron oxides; possibly hematite–magnetite-rich jasper

Banded iron formation (iron-rich chert), possibly jasper

Banded iron formation; alternating microcrystalline quartz (SiO₂) and iron oxides/hydroxides (hematite, magnetite, goethite)

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

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

Chert or chalcedony nodule

Microcrystalline quartz (SiO₂), possibly weathered chert

Jasper

Silicon Dioxide (SiO2), Microcrystalline Quartz

Quartz Geode with Chalcedony

Silicon Dioxide (SiO2)

Quartz Geode (Unbroken)

Silicon Dioxide (SiO2)

Green Jasper / Chert Pebbles

Microcrystalline Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Chert / Chalcedony Nodules

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Jasper

Microcrystalline Quartz (SiO2) with iron oxide impurities

Yellow calcite fragment

Calcite (CaCO₃), likely honey/yellow calcite

Iron-rich metamorphic rock, likely magnetite–hematite-bearing ironstone

Banded or massive iron formation (BIF), chiefly hematite (Fe₂O₃) and magnetite (Fe₃O₄), with quartz and possible iron silicates

Chalcedony (Agate / Quartz Geode Fragment)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Blue calcite (probable)

Calcite, calcium carbonate (CaCO₃)

Raw selenite (gypsum)

Gypsum, CaSO₄·2H₂O; translucent variety selenite

Coquina Limestone (Fossiliferous Limestone)

Calcareous bioclastic sedimentary rock (CaCO3)

Banded iron formation fragment

BIF; hematite–magnetite–chert/quartz assemblage

Quartz

SiO2 (Silicon dioxide)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Clear Quartz

Silicon Dioxide (SiO2)

White Quartz

Silicon Dioxide (SiO2)