Sedimentary (Biogenic Sediment Or Biological Remain)

Chert / Flint (or lithic artifact flake)

Microcrystalline Quartz (SiO2)

Chert (likely flint), possibly chalcedony-rich

Microcrystalline quartz, SiO₂ (quartz/chalcedony)

Fossil shark tooth

Likely fossilized shark tooth, possibly Otodus or Carcharhinus; exact identification requires a sharper, closer image

Mixed beach pebbles and shell fragments

Mostly carbonate rocks, likely limestone/calcarenite, with mollusk-shell bioclasts; exact species cannot be determined visually

Stromatolite

Laminated biogenic sedimentary structure (Cyanobacteria)

Stromatolite Fossil

Stromatolite (Cyanobacteria biogenic sedimentary structure)

Fossiliferous Limestone

Biogenic Sedimentary Rock (primarily CaCO3)

Fossiliferous Limestone

Autochthonous Biogenic Sedimentary Rock (CaCO3)

Fossilized bone or tooth fragment

Indeterminate fossil bone; possibly mammalian or reptilian

Weathered quartz-rich stone (likely chert or quartzite)

Quartzite or microcrystalline quartz (SiO₂); exact identification is uncertain from the image

Calcite

Calcium Carbonate (CaCO3)

Fossil gastropod shell

Calcareous mollusk shell, chiefly aragonite or calcite (likely a large marine gastropod)

Small metallic-looking mineral/rock fragment

Indeterminate from image; possibly galena, hematite, or metallic slag

Banded limestone or marble fragment

Calcite-rich carbonate rock; likely banded marble (CaCO₃)

Chert

Microcrystalline Quartz (SiO2)

Fossil coral fragment

Likely calcitic colonial coral, possibly fossilized scleractinian coral

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with marine fossils

Fossilized cylindrical shell or bone fragment

Indeterminate biogenic carbonate or phosphatic fossil; possible fragment of a tubular shell (e.g., scaphopod) or hollow bone

Fossiliferous Limestone

Biogenic Sedimentary Rock (Calcite, CaCO3)

Chert

Cryptocrystalline Quartz (SiO2)

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Fossilized Tooth Fragment

Vertebrate Fossil (Mammalia indet.)

Oyster Shell Fragment

Crassostrea virginica (or related Bivalvia)

Coquina

Biogenic Limestone (Coquina)

Coquina

Biogenic Limestone (Calcitic)

Fossiliferous Limestone

Biogenic Limestone (CaCO3)

Coquina Limestone

Coquina (Biogenic Limestone)

Fossiliferous Limestone (Coquina / Shell Limestone)

Biogenic Limestone (CaCO3)

Coquina

Biogenic Limestone (Coquina)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Fossiliferous Limestone containing a Brachiopod or Mollusk Impression

Biogenic Sedimentary Rock / Fossiliferous Limestone

Fossiliferous Limestone

Biogenic Sedimentary Rock (primarily CaCO3)

Fossil shark tooth, likely sand tiger shark

Fossilized selachian tooth; possibly *Carcharias* or *Striatolamia*

Chert (Nodule)

Microcrystalline Silica (SiO2)

Chert

Silicon dioxide (SiO2)

Chert

Silicon dioxide (SiO2)

Chert or Flint

Silicon dioxide (SiO2)

Shungite

Shungite (Non-crystalline carbon, C)

Amber (Rough)

Amber (Fossilized Tree Resin, succinite)

Brain Coral Fossil

Family Mussidae or Merulinidae (Order Scleractinia)

Petrified wood (polished/cut slab)

Silicified fossil wood, commonly quartz/chalcedony (SiO₂) replacing wood tissue

Weathered quartz-rich rock, likely chert or quartzite

Quartzite/chert; predominantly microcrystalline quartz (SiO₂), with iron-oxide staining and possible minor feldspar or clay minerals