Sedimentary (Chemically Precipitated)

Green Calcite

Calcium Carbonate (CaCO3)

Yellow Calcite

Calcium Carbonate (CaCO3)

Rough Green Calcite

Calcite (Calcium Carbonate, CaCO3)

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Calcite crystal fragment

Calcite (calcium carbonate, CaCO₃)

Dead Sea Salt Crust

Halite (NaCl)

Chert with Manganese Dendrites / River Silt Overlays

Cryptocrystalline Quartz (SiO2) with Manganese Oxides

Green Jasper

Microcrystalline Quartz (SiO2)

Fossiliferous Limestone

Calcite (CaCO3) matrix with biogenic fragments

Moqui Marble

Ironstone Concretion (Goethite/Hematite)

Sandstone with Manganese Dendrites

Arenite (mostly SiO2) with Manganese Oxide inclusions (MnO2)

Limonite (Ironstone)

Limonite (FeO(OH)·nH2O)

Chert (Flint / Agate Nodule)

Silicon Dioxide (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Limonite / Ironstone

Hydrated ferric oxide (FeO(OH)·nH2O)

Chert or flint nodule

Microcrystalline quartz (SiO₂), likely chalcedony-rich chert

Banded iron formation fragment (likely jasper-rich ironstone)

Banded iron formation (BIF), commonly hematite/goethite with chert or jasper; Fe₂O₃/FeO(OH) and SiO₂

Chert / Flint Pebble with Fossil Cavity

Silicon Dioxide (SiO2)

River Pebble (Greywacke or Chert mix)

Silicon Dioxide (SiO2) with varying mineral impurities

Chert Pebble with Quartz Veining

Microcrystalline Quartz (SiO2)

Liesegang Banded Sandstone (Concretion / Weathered Pebble)

Sandstone showing Liesegang rings / Weathering rind (SiO2 with iron oxides)

Septarian Nodule

Septarian Concretion (Composition: Calcite, Aragonite, and Limestone/Clay)

Sandstone

Arenite (Sedimentary Rock)

Banded Chert

Microcrystalline Quartz (SiO2)

Yellow Calcite

Calcite (Calcium Carbonate, CaCO3)

Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Banded Iron Formation (BIF)

Banded Iron Formation with Hematite and Jasper

Limonite (Iron Ore/Sandstone mixture)

Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix

Quartz Geode / Druzy Quartz

Silicon Dioxide (SiO2)

Red Jasper

Silicon Dioxide with Iron Oxide (SiO2)

Limonite (Yellow Ochre)

Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)

Rounded limestone pebble

Limestone, predominantly calcite (CaCO₃)

Chert with Quartz Vein

Microcrystalline Quartz (SiO2)

Banded Onyx (Green Onyx)

Banded Calcite or Travertine (CaCO3)

Amethyst Geode

Amethyst/Purple Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Orange Calcite

Calcium Carbonate (CaCO3)

Honey Calcite

Calcite (Calcium Carbonate, CaCO3)

Hematite

Iron(III) oxide (Fe2O3)

Banded Iron Formation (BIF) / Chert

Banded Iron Formation (SiO2 with Fe2O3 / Fe3O4)

Quartz with Host Rock

SiO2 (Quartz) with fine-grained Matrix

Banded Iron Formation (BIF)

Banded Iron Formation (Taconite/Itabirite)