Sedimentary (Fossilized)

Belemnite Fossil (Guard)

Belemnoidea (Carbonate/Calcite replacement)

Limonite Concretion

Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)

Petrified Wood

Silicified wood (Quartz variant, SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Sandstone

Arenite (primarily SiO2)

Green Chert (Jasper)

Silicon Dioxide (SiO2)

Quartz (likely a form of massive or vein quartz)

Quartz (SiO₂)

Sandstone with Quartz Veins

Arenite (primarily SiO2 with Fe2O3 staining)

Limestone

Calcium Carbonate (CaCO3)

Sandstone with Secondary Mineral Encrustation

Arenite with Silica/Calcite deposits (SiO2 or CaCO3)

Limestone

Calcium Carbonate (CaCO3)

Chert (Nodular)

Microcrystalline Silica (SiO2)

Chert (Flint nodule)

Chert (SiO2)

Fancy Jasper (Ocean Jasper or River Jasper variant)

Silicon Dioxide with inclusions (SiO2)

Mookaite Jasper

Silicified radiolarite (SiO2)

Jasper

Jasper (Silicon Dioxide, SiO2)

Red Sandstone

Arenite (composed primarily of SiO2 with Fe2O3 cementation)

Gastropod Steinkern (Fossil Snail Internal Mold)

Class Gastropoda (Internal Mold)

Sandstone (with ripple marks)

Arenite (SiO2 primarily)

Green Chert

Microcrystalline Quartz (SiO2)

Chert (and Petrified Wood)

Silicon Dioxide (SiO2)

Chert (specifically Jasper or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone with Liesegang Rings

Arenite with secondary Iron oxide (Limonite/Goethite) precipitation

Red Jasper (possibly Chert/Argillite)

Jasper (SiO2) with iron oxide inclusions

Ironstone (Limonitic Concretion)

Limonite (FeO(OH)·nH2O) with Goethite and Hematite inclusions

Ironstone Concretion (Iron-rich Mudstone)

Siderite / Geothite concretion (FeCO3 / FeO(OH))

Chert (or Flint)

Chert (a cryptocrystalline variety of quartz, SiO2)

Green Banded Chert (Agate/Jasper)

Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite

Greenstone / Glauconitic Siltstone

Metabasalt or Glauconite-rich Sedimentary Rock

Quartz Vein in Host Rock

Quartz (SiO2) in Mafic or Sedimentary Matrix

Pumice or Tufa/Travertine

Pumice (if igneous) or Calcareous Tufa (if sedimentary)

Amber Chert (Jasper)

Microcrystalline Quartz (SiO2)

Jasper

Silicon dioxide (SiO2) with iron oxide impurities

Chert

Microcrystalline Quartz (SiO2)

Chert (varieties: Flint or Chalcedony)

Microcrystalline silica (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Chalcedony (Botryoidal Agate)

Silicon Dioxide (SiO2)

Chert (specifically Flint or Common Opal/Chalcedony mix)

Microcrystalline Quartz (SiO2)

Chalcedony (Yellow Agate/Chert)

Silicon Dioxide (SiO2)

Shungite

Non-crystalline carbon (high-carbon metamorphic rock)

Kyanite in Quartz

Kyanite (Al2SiO5) with Quartz (SiO2) matrix

Almandine Garnet

Iron aluminum silicate - Fe3Al2(SiO4)3