Sedimentary (Chemically Precipitated)

Chert (Arrowhead Preform or Point)

Chert (Microcrystalline Quartz, SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Chert or Jasper

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variant)

Microcrystalline Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Chert

Microcrystalline Quartz (SiO2)

Banded Chert

Microcrystalline Quartz (SiO2)

Chert (Heart-shaped Pebble)

Cryptocrystalline quartz (SiO2)

Chert (Chalcedony/Agate variety)

Microcrystalline Quartz (SiO2)

Chert (Jasper)

Silicon Dioxide (SiO2)

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Banded Chert

Sedimentary Cryptocrystalline Quartz (SiO2)

Marble

Recrystallized Calcite (CaCO3)

Limonite / Ironstone

Hydrated Iron Oxide (FeO(OH)·nH2O)

Limestone

Calcium Carbonate (CaCO3)

Banded Chert

Silicon Dioxide (SiO2) with impurities

Chert (Jasper)

Silicon Dioxide (SiO2)

Glauconite (Sandstone or Shale)

Glauconite (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2

Bog Iron / Limonite Concretion

Goethite/Limonite mixture (FeO(OH)·nH2O)

Chert (or Jasper)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper)

Silicon Dioxide (SiO2)

Bauxite

Bauxite (Al2O3·2H2O)

Limestone

Calcium Carbonate (CaCO3)

Bauxite

Bauxite (principal ore of aluminum, primarily Al(OH)3)

Bauxite

Bauxite (Al2O3·nH2O)

Bauxite

Bauxite (Al2O3·nH2O)

Quartz pebble

Silicon dioxide (SiO2)

Limestone

Sedimentary Rock (Primarily CaCO3)

Chert

Microcrystalline Quartz (SiO2)

Muscovite Mica (with Schist)

Muscovite - KAl2(AlSi3O10)(OH)2

Chert (Common Opal/Jasper variety)

Silicon Dioxide (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Basalt with Caliche Crust

Aphanitic Mafic Igneous Rock with Calcium Carbonate (CaCO3) coating

Quartz Pebble

Silicon Dioxide (SiO2)

Weathered quartz-rich stone, possibly fossiliferous limestone

Indeterminate; likely calcite-rich limestone (CaCO₃) or weathered quartz-bearing rock

Chert

Microcrystalline Quartz (SiO2)

Turtle Stone / Septarian Nodule (Water-worn)

Septarian Concretion

Chert

Microcrystalline Quartz (SiO2) with iron oxide staining

Chert (Flint)

Microcrystalline Quartz (SiO2)