Sedimentary (Chemically Precipitated Mineral)

Chert (Flint Nodules)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Red Jasper (beads)

Silicon Dioxide (SiO2) with iron inclusions

Milky Quartz Pebble with Iron Inclusions

Silicon Dioxide (SiO2) with iron oxide impurities

Banded Sandstone

Quartz Arenite (with iron oxide banding)

Limonite-stained Chert

Microcrystalline Quartz (SiO2) with Goethite/Limonite (FeO(OH)·nH2O)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Quartz (Microcrystalline/Gravel)

Silicon Dioxide (SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Banded Sandstone (Liesegang Rings)

Sedimentary sandstone with Iron oxide precipitates

Chert Pebble

Microcrystalline quartz (SiO2)

Limonite (Iron Ore)

Hydrated ferric oxide (FeO(OH)·nH2O)

Ferruginous Sandstone (Gozzan/Ironstone)

Arenite with Limonite/Goethite cement (FeO(OH)·nH2O)

Chalcedony (Common Opal/Chert variety)

Silicon Dioxide (SiO2)

Chert (Jasper)

Silicon Dioxide (SiO2)

Banded Calcite (often sold as 'Ocean Jasper' or 'Caribbean Calcite' variant)

Calcium Carbonate (CaCO3) with potential Aragonite inclusions

Orange Calcite

Calcium Carbonate (CaCO3)

Septarian Nodule

Septarian Concretion (Calcite, Aragonite, Limestone)

Aragonite

Aragonite (Calcium Carbonate - CaCO3)

Gold Flakes

Native Gold (Au)

Bauxite (Concretionary)

Bauxite (Al(OH)3, AlO(OH))

Banded Iron Formation

Banded Iron Formation (BIF)

Banded Iron Formation (BIF) / Jasper

Banded Iron Formation (SiO2 with Fe2O3 / Fe3O4)

Septarian Nodule (Dragon Stone)

Septarian concretion (composition: Calcium Carbonate / Calcite, Aragonite, and Limestone/Clay)

Liesegang Banded Sandstone (Wonderstone)

Ferruginous Sandstone with Liesegang Rings

Quartzite River Stone

Metamorphosed Quartz-rich Sandstone (SiO2)

Dendritic Limestone

Calcite with Manganese Oxide (Manganese Dendrites)

Moqui Marble

Iron Oxide Concretion (Limonite/Hematite over Sandstone)

Septarian Nodule (or Mudstone with Septarian Cracking)

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

Jasper with Quartz Vein

Silicon Dioxide (SiO2) with impurities

Black Limestone with Calcite Veining

Limestone (CaCO3) with Calcite (CaCO3) inclusions

Jasper

Jasper (Silicon Dioxide, SiO2)

Bauxite

Alumina-rich rock (consisting of Gibbsite, Boehmite, and Diaspore)

Travertine (Tufa)

Chemical Sedimentary Rock / Travertine (CaCO3)

Tumbled chert or flint pebble

Microcrystalline quartz (SiO₂), likely chert; exact variety uncertain from the image

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Obsidian

Obsidian (Volcanic Glass)

Quartz (Quartzite or Quartz Pebble)

Silicon Dioxide (SiO2)

Quartz (Common Grains)

Silicon Dioxide (SiO2)