Fossil Shell
Phylum Mollusca (Gastropod fossil)
fossil
Category
Mineral (Biogenic Replacement)
Browse mineral (biogenic replacement) specimens identified by the Rock Identifier community.
Fossil Sea Urchin (Echinoid)
Echinoidea fossil (often replaced by silica or calcite)
fossil
Fossil brachiopod or bivalve shell fragment
Likely a fossilized, ribbed brachiopod; exact genus/species cannot be determined from the image
fossil
Fossilized Bivalve Shell
Bivalvia (fossil specimen)
sedimentary
Tiger's Eye
Pseudomorph of quartz after crocidolite (SiO2)
metamorphic
Fossilized Sea Urchin (Echinoid)
Echinoidea (Class) - likely replaced by Calcite or Quartz
sedimentary
Polished ammonite fossil
Ammonoidea; likely a polished ammonite fragment, possibly an aptychus-associated piece
fossil
Fossil shark tooth
Likely a fossilized shark tooth, possibly Carcharhinus or a related requiem shark; exact species is indeterminate from the image.
fossil
Fossil shark tooth
Likely fossilized shark tooth, possibly *Carcharocles* or *Otodus* species
fossil
Fossilized Shell Fragment
Bivalvia or Gastropoda (Class) fragment
fossil
Fossilized Fish (Lepidotes)
Lepidotes sp. (Order: Lepisosteiformes)
sedimentary
Fossilized bivalve shell
Bivalvia indeterminate; likely a preserved clam or cockle shell, composed mainly of calcium carbonate (CaCO₃)
fossil
Petrified Wood
Silicified wood (SiO2)
fossil
Sphalerite
Zinc sulfide (Zn, Fe)S
mineral
Galena
Lead(II) sulfide (PbS)
mineral
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
mineral
Galena with Pyrite
Lead Sulfide (PbS) associated with Iron Sulfide (FeS2)
mineral
Fossilized Shark Tooth (Partial) or Coprolite
Elasmobranchii (fossil) or Coprolite (trace fossil)
fossil
Polished brown flint/chert (likely)
Microcrystalline quartz, SiO₂ (chalcedonic flint/chert)
sedimentary
Fossilized Dinosaur Bone
Perineralized Bone (Fluorapatite/Quartz replacement)
fossil
Rhodonite
Rhodonite (Manganese Iron Magnesium Calcium Silicate - (Mn,Fe,Mg,Ca)SiO3)
mineral
Fossil / Permineralized Bone
Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Goethite/Hematite Nodule
Goethite (FeO(OH)) and Hematite (Fe2O3)
mineral
Water and Silt (Sedimentary Environment)
Suspended Sediment / H2O (dihydrogen monoxide)
sedimentary
Fossilized Nut / Coprolite / Concretion
Trace Fossil / Permineralized Plant Material
fossil
Dendritic jasper (brecciated or orbicular jasper)
Microcrystalline quartz (SiO₂) with iron-oxide inclusions
mineral
Polished orbicular jasper (likely ocean jasper)
Microcrystalline quartz (SiO₂) with chalcedony, iron oxides, and orbicular alteration textures
mineral
Tumbled yellow jasper (likely silicified/iron-stained chert)
Microcrystalline quartz/chalcedony, SiO₂, colored by iron oxides and darker inclusions
mineral
Gastropod shell fragment
Calcareous mollusk shell; primarily aragonite or calcite (CaCO₃)
fossil
Pyrite
Iron Disulfide (FeS2)
mineral
Chalcedony (Milky Agate/Quartz)
Silicon Dioxide (SiO2)
mineral
Pyrite-rich Ore
Pyrite (FeS2) with secondary minerals
mineral
Pyrite (Iron Pyrites)
Iron Sulfide (FeS2)
mineral
Polished ocean jasper
Orbicular jasper (microcrystalline quartz, SiO₂)
mineral
Shark Tooth Fossil
Vertebrate fossilized tooth
fossil
Polished banded stone, likely zebra jasper
Zebra jasper (banded microcrystalline quartz, chiefly SiO₂, with iron-oxide and carbonate impurities)
metamorphic
Crinoid stem fossil
Crinoidea
fossil
Fossil shark tooth, likely sand tiger shark
Fossilized selachian tooth; possibly *Carcharias* or *Striatolamia*
fossil
Fossilized Echinoid (Sea Urchin) or Brachiopod
Echinoidea / Invertebrate Fossil
fossil
Fossilized bivalve or brachiopod shell
Mineralized carbonate shell, commonly calcite (CaCO₃); exact taxon indeterminate from image
fossil