Rock Identifier

Category

Mineral (Biogenic Replacement)

Browse mineral (biogenic replacement) specimens identified by the Rock Identifier community.

Bivalve Fossil (Clam Fossil) (Class Bivalvia (likely Gryphaea or similar Order)) — fossil

Bivalve Fossil (Clam Fossil)

Class Bivalvia (likely Gryphaea or similar Order)

Chert (Chalcedony/Agate variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Chalcedony/Agate variety)

Silicon Dioxide (SiO2)

Chrysanthemum Stone (Chrysanthemum Stone (Calcite/Celestite/Strontianite in Limestone)) — sedimentary

Chrysanthemum Stone

Chrysanthemum Stone (Calcite/Celestite/Strontianite in Limestone)

Chert (Flint) with Glauconite (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Flint) with Glauconite

Microcrystalline Quartz (SiO2)

Fossil Shell (Invertebrate fossil (Mollusca)) — fossil

Fossil Shell

Invertebrate fossil (Mollusca)

Fossilized Coral (Rugose Coral / Hexagonaria (Fossilized calcium carbonate)) — fossil

Fossilized Coral

Rugose Coral / Hexagonaria (Fossilized calcium carbonate)

Queen Conch Shell (Biogenic Calcium Carbonate) (Aliger gigas (synonym Strombus gigas); Composition: Aragonite (CaCO3)) — mineral

Queen Conch Shell (Biogenic Calcium Carbonate)

Aliger gigas (synonym Strombus gigas); Composition: Aragonite (CaCO3)

Fossilized ammonite (Ammonoidea (likely a ribbed Jurassic–Cretaceous ammonite), replaced mainly by calcite or silica) — fossil

Fossilized ammonite

Ammonoidea (likely a ribbed Jurassic–Cretaceous ammonite), replaced mainly by calcite or silica

Fossilized Brachiopod (Phylum Brachiopoda) — fossil

Fossilized Brachiopod

Phylum Brachiopoda

Fossilized Shark Tooth (Chondrichthyes (Class)) — fossil

Fossilized Shark Tooth

Chondrichthyes (Class)

Crinoid Stem Fossil (Crinoid columnal (Echinodermata)) — fossil

Crinoid Stem Fossil

Crinoid columnal (Echinodermata)

Fossilized Sand Tiger Shark Tooth (Carcharias taurus / Striatolamia macrota (mineralized as Hydroxylapatite/Francolite)) — sedimentary (fossil)

Fossilized Sand Tiger Shark Tooth

Carcharias taurus / Striatolamia macrota (mineralized as Hydroxylapatite/Francolite)

sedimentary (fossil)

Fossil Shark Tooth (Chondrichthyes tooth fossil) — fossil

Fossil Shark Tooth

Chondrichthyes tooth fossil

Starfish Fossil (Asteroidea fossil) — fossil

Starfish Fossil

Asteroidea fossil

Chert (Flint) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Agate variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Jasper/Agate variety)

Silicon Dioxide (SiO2)

Sand Tiger Shark Tooth (Carcharias taurus) — fossil

Sand Tiger Shark Tooth

Carcharias taurus

Gastropod Fossil (Class Gastropoda (fossilized)) — fossil

Gastropod Fossil

Class Gastropoda (fossilized)

Fossil shell fragment (likely brachiopod or bivalve) (Indeterminate fossilized carbonate shell; likely Brachiopoda or Bivalvia) — fossil

Fossil shell fragment (likely brachiopod or bivalve)

Indeterminate fossilized carbonate shell; likely Brachiopoda or Bivalvia

Pyrite (Fool's Gold) in Matrix (Iron Disulfide (FeS2)) — mineral

Pyrite (Fool's Gold) in Matrix

Iron Disulfide (FeS2)

Chalcedony (Chert/Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chalcedony (Chert/Flint)

Silicon Dioxide (SiO2)

Jasper (Silicon dioxide (SiO2) with impurities) — sedimentary

Jasper

Silicon dioxide (SiO2) with impurities

Yellow Jasper (Tectosilicates (SiO2) with Goethite/Iron oxide inclusions) — sedimentary

Yellow Jasper

Tectosilicates (SiO2) with Goethite/Iron oxide inclusions

Fossil shell fragment (Likely a fossilized brachiopod or bivalve; exact taxon cannot be determined from the image) — fossil

Fossil shell fragment

Likely a fossilized brachiopod or bivalve; exact taxon cannot be determined from the image

Sphalerite (Zinc Sulfide (Zn,Fe)S) — mineral

Sphalerite

Zinc Sulfide (Zn,Fe)S

Jasper (Silicon dioxide (SiO2)) — sedimentary

Jasper

Silicon dioxide (SiO2)

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Limonite with Galena (FeO(OH)·nH2O (Limonite) and PbS (Galena)) — mineral

Limonite with Galena

FeO(OH)·nH2O (Limonite) and PbS (Galena)

Fossil Shark Tooth (Chondrichthyes (Class)) — fossil

Fossil Shark Tooth

Chondrichthyes (Class)

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Galena with Pyrite on Matrix (Lead(II) sulfide (PbS) with Iron disulfide (FeS2)) — mineral

Galena with Pyrite on Matrix

Lead(II) sulfide (PbS) with Iron disulfide (FeS2)

Tiger's Eye (Silicon Dioxide with Crocidolite (SiO2)) — mineral

Tiger's Eye

Silicon Dioxide with Crocidolite (SiO2)

Chert (Chert (SiO2)) — sedimentary

Chert

Chert (SiO2)

Fossil Coral (Cnidaria Anthozoa (Fossilized)) — sedimentary

Fossil Coral

Cnidaria Anthozoa (Fossilized)

Gastropod Fossil (Snail Internal Mold) (Gastropoda; internal mold (steinkern), often composed of Calcium Carbonate (CaCO3) or Silica (SiO2)) — sedimentary

Gastropod Fossil (Snail Internal Mold)

Gastropoda; internal mold (steinkern), often composed of Calcium Carbonate (CaCO3) or Silica (SiO2)

Green Fluorite (Fluorite (Calcium Fluoride, CaF2)) — mineral

Green Fluorite

Fluorite (Calcium Fluoride, CaF2)

Shark Tooth Fossil (Chondrichthyes fossil) — fossil

Shark Tooth Fossil

Chondrichthyes fossil

Rhodonite (Manganese Inosilicate (Mn,Fe,Mg,Ca)SiO3) — mineral

Rhodonite

Manganese Inosilicate (Mn,Fe,Mg,Ca)SiO3

Megalodon Shark Tooth (Otodus megalodon) — fossil

Megalodon Shark Tooth

Otodus megalodon

Brachiopod Fossil in Limestone (Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)) — sedimentary

Brachiopod Fossil in Limestone

Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Rhodochrosite (Manganese Carbonate (MnCO3)) — mineral

Rhodochrosite

Manganese Carbonate (MnCO3)