Sedimentary (Chemically Precipitated)

Limonite/Goethite on Shale

Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock

Quartz-veined Siltstone

Siltstone with Quartz (SiO2) veins

Greywacke with Quartz Veins

Lithic Sandstone (Greywacke) with SiO2 inclusions

Banded Iron Formation (BIF) / Tiger Iron variety

Banded Iron Formation (predominantly Hematite, Magnetite, and Chert/Quartz - SiO2 + Fe2O3)

Manganese-coated Sandstone

Clastic sedimentary rock with Manganese Oxide (often Pyrolusite or Psilomelane)

Fossiliferous Limestone (containing Brachiopods)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Chert (Field Stone)

Microcrystalline Quartz (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Caliche (also known as hardpan, calcrete, kankar)

Primarily composed of calcium carbonate (CaCO₃), often mixed with other minerals like quartz, clay minerals, and iron oxides.

Chert (Jasper-like Silicate)

Microcrystalline quartz (SiO2)

Basalt with Caliche Crust

Aphanitic Mafic Igneous Rock with Calcium Carbonate (CaCO3) coating

Sandstone (Banded)

Clastic Sedimentary Rock (primarily Quartz, SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (Common Opal/Jasper variety)

Cryptocrystalline Quartz (SiO2)

Chert (specifically Red Chert/Jasper variety)

Silicon Dioxide (SiO2)

Chert (Flint)

Chert (Silicon Dioxide, SiO2)

Chert (specifically Flint or Common Chert)

Chert (Cryptocrystalline Silica, SiO2)

Chert (specifically Red Chert/Jasper nodule)

Microcrystalline Quartz (SiO2)

Chert Geode with Quartz Druzy

Microcrystalline Quartz (SiO2) with macrocrystalline Quartz

Chert (Jasper)

Silicon Dioxide (SiO2)

Chert (specifically Jasper/Flint)

Microcrystalline Quartz (SiO2)

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Banded Calcite (often marketed as Caribbean Calcite)

Calcium Carbonate (CaCO3) + Aragonite

Chert (specifically Yellow or Brown Chert / Jasper)

Silicon Dioxide (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with Hematite impurities

Chert with Asphaltum (or Tar)

Silica (SiO2) with natural Bitumen/Asphaltum

Chert (Flint)

Chert (Silica, SiO2)

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Yellow Calcite

Calcium Carbonate (CaCO3)

Chert (Common Opal/Jasper variety)

Silicon Dioxide (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Chert

Chert (variant of microcrystalline quartz)

Wonderstone

Rhyolite (Silicon Dioxide with Iron Oxide impurities)

Bog Iron / Limonite Concretion

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

Chert (Flint/Chalcedony)

Microcrystalline Quartz (SiO2)

Chert (often called Jasper in this color variety)

Microcrystalline Quartz (SiO2)

Blue Calcite

Calcium Carbonate (CaCO3)

Honey Calcite

Calcium Carbonate (CaCO3)

Chert (specifically Jasper/Brown Chert)

Silicon Dioxide (SiO2)

Ironstone (with possible Hematite/Limonite coating)

Ironstone (Fe-rich sedimentary rock)

Calcite

Calcium Carbonate (CaCO3)

Jasper (Iron-rich)

Silicon Dioxide (SiO2) with Hematite (Fe2O3) impurities