Fossil

Chert (River Pebble)

Silicon Dioxide (SiO2)

Shale

Laminated Mudstone (Shale)

Chert Concretion (Flint)

Silicon Dioxide (SiO2)

Sandstone Concretion

Ferruginous Sandstone Concretion

Ironstone concretion / Limonitic Sandstone

Goethite/Hematite Cemented Sandstone (Hydrated Iron Oxide)

Banded Chert

Microcrystalline Quartz (SiO2)

Concretionary Sandstone

Clastic Sedimentary Rock (Sandstone with secondary mineral cementation)

Quartzite River Rock with Dendrites

Metamorphosed Quartz-rich Sandstone with Manganese Oxide (MnO2) inclusions

Sandstone

Arenite (SiO2 based)

Sandstone (with Concretion)

Arenite / Quartzose Sandstone

Sandstone

Arenite (CaCO3/SiO2 cemented quartz)

Limestone (Buff/Tan)

Calcium Carbonate (CaCO3)

Crushed Limestone

Calcium Carbonate (CaCO3)

Dendritic Agate

Chalcedony (SiO2) with manganese/iron oxide inclusions

Limestone Cobble

Sedimentary Calcium Carbonate (CaCO3)

Sandstone Concretion

Sedimentary Clastic Rock (Silicate-rich)

Sandstone (Ferruginous)

Arenite (SiO2 with Iron Oxide impurities)

Sandstone Concretion

Clastic Sedimentary Concretion (typically Quartz/Silica with Iron Oxide)

Siltstone

Siltstone (fined-grained clastic sedimentary rock)

Stromatolite

Biogenic Sedimentary Rock (composed predominantly of CaCO3)

Sandstone (Weathered Cobble)

Clastic Sedimentary Rock (primarily SiO2)

Cone-in-cone structure

Cone-in-cone structure

Fossilized Coral

Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)

Limonite Concretion

Limonite (Hydrated Iron Oxide) FeO(OH)·nH2O

Bivalve Fossil (Internal Mold)

Class Bivalvia (Phylum Mollusca)

Fossil Coral (Rugose Coral)

Rugosa (extinct order); typically composed of Calcite (CaCO3) or replaced by Quartz (SiO2)

Agatized Fossil or Chalcedony Nodule

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Petrified Wood (Silicified Fossil)

Silicified Wood (SiO2)

Bivalve Fossil (Shell Fragment)

Class Bivalvia (Calcium Carbonate - CaCO3)

Favosites Fossil (Honeycomb Coral)

Favosites sp. (Extinct genus of tabulate coral)

Echinoidea (Fossil Sea Urchin)

Echinodermata Echinoidea

Cockle Shell (Fossil or Recent)

Class Bivalvia, Family Cardiidae (e.g., Cerastoderma edule for common cockle)

Fossiliferous Limestone with Crinoid Stem fragment

Calcite (CaCO3) containing Crinoidea fossils

Fossiliferous Limestone

Limestone (CaCO3) with Crinoid/Bivalve fossils

Sandstone Concretion

Septarian or Carbonate-cemented Sandstone Concretion

Shale

Shale (clay-rich mudstone)

Sandstone with Iron Staining

Arenite (SiO2 with Fe2O3)

Sandstone

Arenite (SiO2 primarily)

Sandstone (Quartzose Sandstone)

Arenite

Anthracite Coal

Anthracite

Sandstone

Arenite (primarily SiO2)

Limestone

Calcium Carbonate (CaCO3)