Organic Specimen (Fossil)

Pyrite

Iron Sulfide (FeS2)

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily Quartz with Fe2O3 staining)

Coal

Bituminous or sub-bituminous coal (carbonaceous rock)

Limestone

Calcium Carbonate (CaCO3)

Sandstone

Clastic Sedimentary Rock

Sandstone Concretion

Sedimentary Concretion (Quartz sandstone with iron oxide cement)

Limestone

Calcium Carbonate (CaCO3)

Fossil shark teeth

Likely fossilized shark teeth; exact species indeterminate from the image, possibly Carcharhiniformes or related taxa

Concretion

Sedimentary Concretion (e.g., Siderite or Ironstone)

Limestone

Limestone (Calcium Carbonate, CaCO3)

Sandstone Concretion

Clastic sedimentary rock (primarily Silica, SiO2, or Calcium Carbonate, CaCO3)

Sandstone

Arenite (primarily SiO2)

Limestone

Calcium Carbonate (CaCO3)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Mosasaur Tooth Fossil

Mosasauridae (likely Prognathodon or Mosasaurus)

Shale

Fissile Mudrock (Clay-rich Sedimentary Rock)

Pyrite

Pyrite (Iron Disulfide), FeS2

Vuggy Chert / Silicified Limestone

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Fossilized Shark Tooth (Otodus obliquus)

Otodus obliquus (Mineral composition: Bio-apatite/Calcium Phosphate replaced by various minerals)

Sandstone and Mixed Rock Assemblage

Clastic Sedimentary Rock / Quartz Arenite

Sandstone and Gravel Aggregate

Clastic Sedimentary Rock / Quartzose Sandstone

Chert Nodule in Limestone

Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)

Banded Sandstone Peabble

Arenite with iron oxide banding

Ferruginous Sandstone (Ironstone)

Iron-rich Arenite

Limestone

Limestone (Calcium Carbonate: CaCO3)

Sandstone

Arenite (SiO2 predominantly)

Fossiliferous Limestone

Biogenic Sedimentary Rock (primarily CaCO3)

Cone-in-cone structure (Limestone)

Cone-in-cone structure (Secondary Sedimentary Structure)

Limestone with Chert Nodules

Sedimentary Calcium Carbonate (CaCO3) with Microcrystalline Silica (SiO2) inclusions

Fossilized Shark Tooth

Carcharodon (Galeocerdo sp. or Lamniform)

Sandstone (likely Quartzose)

Arenite (primarily SiO2)

Sandstone

Arenite/Quartz Arenite

Limestone (specifically Fossiliferous Limestone)

Calcium Carbonate (CaCO3)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Fossil Sea Urchin (Echinoid)

Echinoidea fossil (often replaced by silica or calcite)

Fossil Shell

Phylum Mollusca (Gastropod fossil)

Limestone

Limestone (CaCO3)

Banded chert or siliceous mudstone

Microcrystalline quartz (chalcedony), SiO₂; possibly ferruginous shale

Limestone

Calcium Carbonate (CaCO3)

Petoskey Stone

Hexagonaria percarinata

Red Sandstone

Arenite with Hematite cementation

Flesh-toned Siltstone

Siltstone (composed of microscopic Quartz and Feldspar grains)