Organic Specimen (Fossil)

Siltstone

Siltstone (primarily composed of microcrystalline Quartz and Feldspar)

Siltstone

Siltstone

Sandstone

Arenite (SiO2 based)

Echinoid Fossil (Sea Urchin Fossil)

Echinoidea (phylum Echinodermata), often preserved as Calcite (CaCO3)

Ironstone Concretion (Nutstone)

Ironstone (with High Limonite/Hematite Content)

Concretion or Geode (unbroken)

Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.

Sandstone (Ferruginous)

Arenite with Iron-Oxide Cement

Limestone

Calcite (CaCO3)

Sandstone

Arenite (primarily SiO2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Sandstone (Stream-rounded Cobble)

Arenite (composed primarily of SiO2, Silica)

Sandstone

Arenite (composed primarily of SiO2)

Ferruginous Sandstone (Gritstone)

Arenite with Iron-Oxide Cement (SiO2 with Fe2O3 and FeO(OH))

Amber

Succinite (fossilized resin)

Limestone

Calcium Carbonate (CaCO3)

Sandstone

Arenite (primarily SiO2)

Chert Nodule (Commonly known as a Flint or River Cobble)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Red Mudstone (Siltstone)

Lutite (primarily Quartz and Clay minerals with Hematite)

Sandstone (Ferruginous)

Arenite (with Iron Oxide)

Limestone

CaCO3 (principally composed of Calcite)

Flexicalymene Trilobite Fossil

Flexicalymene meeki (Order Phacopida, Family Calymenidae)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Ferruginous Sandstone (Ironstone)

Ferruginous Sandstone / Limonite-cemented Quartz Sandstone

Chert (with small quartz inclusion)

Microcrystalline Silica (SiO2)

Sandstone (likely Quartzose Sandstone)

Arenite (SiO2 based)

Red Sandstone

Sandstone (mainly SiO2 with Iron Oxide cement)

Concretion

Septarian concretion (likely containing Calcite or Siderite)

Sandstone (likely Arkosic or Lithic Sandstone)

Arenite (SiO2 based with mineral inclusions)

Slate

Foliated Metamorphic Rock (Mainly composed of Quartz, Illite, Chlorite)

Sandstone

Arenite (SiO2 principal)

Sandstone

Arenite (SiO2 principal)

Glauconitic Sandstone

Glauconitic Sandstone (Greensand)

Sandstone

Arenite (primarily SiO2)

Ironstone Concretion / Goethite Nodules

Ironstone (composed primarily of Goethite FeO(OH) and Limonite)

Limestone

Sedimentary rock composed of Calcium Carbonate (CaCO3)

Ammonite Fossil

Ammonoidea (primarily composed of Calcite, CaCO3, or Pyrite)

Dendritic Agate (also known as Dendritic Siltstone or Mudstone)

Silicon Dioxide with Manganese/Iron Oxide inclusions (SiO2 + MnO2)

Sandstone

Arenite (SiO2 with Fe2O3)

Sandstone (Red Arkose)

Sandstone (Arkose variant, primarily SiO2 with KAlSi3O8)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Red Sandstone

Arenite (primarily Quartz SiO₂ with Hematite Fe₂O₃ staining)

Sandstone

Arenite