Sedimentary (Biogenic Sediment Or Biological Remain)

Bivalve Shell (Fossil or Contemporary)

Class Bivalvie (various genera and species of clams, cockles, etc.)

Spondylus Oyster Calcification / Fossilized Oyster

Spondylus (Thorny Oyster) / Calcium Carbonate (CaCO3)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Seashell Fragment (Aragonite/Calcite)

Calcium Carbonate (CaCO3) - Shell fragment

Zebra Rock (Zebra Stone / Ribbon Stone)

Siltstone with Ferruginous Banding (Primarily Quartz, Kaolinite, and Hematite)

Human Skin (Epidermis/Dermis)

Integumentary tissue (High content of hydroxyapatite in bones, though the surface is biological)

Petrified Wood

Silicified Wood (SiO2)

Fossiliferous Limestone with Brachiopod

Phylum Brachiopoda in calcitic matrix

Fossiliferous Limestone (with Crinoids/Coral)

Fossiliferous Limestone (CaCO3)

Pearl

Pearl (Calcium Carbonate with organic conchiolin, CaCO3)

Geode with Quartz and Chalcedony

Silicon Dioxide (SiO2)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Fossilized Shell in Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Coralline Algae / Maerl

Lithothamnion (Biogenic Calcium Carbonate)

Fossiliferous Limestone

Calcium Carbonate - CaCO3

Fossil Coral

Cnidaria fossil (often Calcium Carbonate / CaCO3)

Fossilized Brachiopod Shell in Matrix

Phylum Brachiopoda (typically Calcium Carbonate or Chitinophosphatic)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Water and Silt (Sedimentary Environment)

Suspended Sediment / H2O (dihydrogen monoxide)

Coral Rock (Coquina)

Biogenic Limestone (Calcium Carbonate - CaCO3)

Fossiliferous Chert (Gryphaea Fossil)

Silicon Dioxide (SiO2) with Calcitic Mollusk Remnants

Limestone (Flagstone)

Fossiliferous Limestone (CaCO3)

Gastropod Steinkern (Internal Mold Fossil)

Gastropoda (Class); Internal mold or 'Steinkern' composed of Calcium Carbonate (CaCO3) or Sedimentary matrix

Fossiliferous Chert (with Fossil Shells)

Silicon Dioxide (SiO2) with biogenic inclusions

Pearl (in a decorative hair comb setting)

Calcium carbonate (CaCO3) primarily as Aragonite, bonded with Conchiolin

Granitic Sand

Detrital sediment (predominantly Quartz, Feldspar, and Mica)

Pearl

Aragonite and Calcite (CaCO3) with Conchiolin

Pyrite

Iron Sulfide (FeS2)

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Hag Stone (Banded Chert or Limestone with Borehole)

Microcrystalline Quartz (Chert) or Calciferous Siltstone (CaCO3/SiO2)

Bay Scallop Shell

Argopecten irradians (Biogenic Calcium Carbonate / CaCO3)

Oyster Shell (Aragonite/Calcite)

Calcium Carbonate (CaCO3)

Brachiopod Fossil

Phylum Brachiopoda (likely Order Rhynchonellida or Spiriferida)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Fossiliferous Limestone (Shell Fragment)

Biogenic Limestone (Calcium Carbonate / CaCO3)

Jasper containing fossilized inclusions

Silicon Dioxide (SiO2) with trace impurities and biogenic inclusions

Sea Shell (Fighting Conch Fragment)

Calcium Carbonate (CaCO3) - Strombus alatus fragment

Fossil Bivalve Shell

Class Bivalvia (e.g., Veneriidae family)

Petrified Wood (Agatized/Silicified Wood)

Silicified Wood / Chalcedony (SiO2)

Fossiliferous Limestone (containing Brachiopods)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Conglomerate

Conglomerate (clastic sedimentary rock)

Fossil Shell in Sedimentary Matrix

Bivalvia (fossil) in Calcium Carbonate Matrix