Rock Identifier

Category

Mineral (Biogenic Replacement)

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

Hematite Nodular Iron Ore (Hematite (Fe2O3)) — mineral

Hematite Nodular Iron Ore

Hematite (Fe2O3)

Chalcedony (Grey/White Agate) (Silicon Dioxide (SiO₂)) — mineral

Chalcedony (Grey/White Agate)

Silicon Dioxide (SiO₂)

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

Chert

Chert (Microcrystalline Quartz, SiO2)

Fossilized Gastropod Shell (Class Gastropoda (Fossil)) — sedimentary

Fossilized Gastropod Shell

Class Gastropoda (Fossil)

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

Jasper

Silicon dioxide (SiO2) with impurities

Quartz (Chert/Chalcedony variety) (Silicon Dioxide (SiO2)) — mineral

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Hematite with Magnetite (Iron Oxide (Fe2O3)) — mineral

Hematite with Magnetite

Iron Oxide (Fe2O3)

Red Jasper (Chert) (Silicon Dioxide (SiO2) with iron oxide inclusions) — sedimentary

Red Jasper (Chert)

Silicon Dioxide (SiO2) with iron oxide inclusions

Red Jasper (Jasper (Silicon Dioxide, SiO2)) — sedimentary

Red Jasper

Jasper (Silicon Dioxide, SiO2)

Shark Tooth Fossil (Vertebrate fossilized tooth (various genera such as Carcharodon, Otodus, or Negaprion)) — fossil

Shark Tooth Fossil

Vertebrate fossilized tooth (various genera such as Carcharodon, Otodus, or Negaprion)

Jasper (Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)) — sedimentary

Jasper

Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)

Fossiliferous Limestone / Petrifaction (Sedimentary rock with fossil inclusions / Calcium Carbonate (CaCO3)) — fossil

Fossiliferous Limestone / Petrifaction

Sedimentary rock with fossil inclusions / Calcium Carbonate (CaCO3)

Magnetite / Hematite mix (Iron Ore) (Fe3O4 (Magnetite) / Fe2O3 (Hematite)) — mineral

Magnetite / Hematite mix (Iron Ore)

Fe3O4 (Magnetite) / Fe2O3 (Hematite)

Fossilized Bivalve Shell (Bivalvia (Phylum Mollusca)) — fossil

Fossilized Bivalve Shell

Bivalvia (Phylum Mollusca)

Jasper (Microcrystalline quartz (SiO2)) — sedimentary

Jasper

Microcrystalline quartz (SiO2)

Brown Quartz (Jasper or Chert) (Silicon Dioxide (SiO2)) — sedimentary

Brown Quartz (Jasper or Chert)

Silicon Dioxide (SiO2)

Tiger's Eye (Tiger's eye (Pseudomorph of Quartz after Crocidolite), SiO2) — metamorphic

Tiger's Eye

Tiger's eye (Pseudomorph of Quartz after Crocidolite), SiO2

Fossilized Bone (Permineralized Vertebrate Bone) — fossil

Fossilized Bone

Permineralized Vertebrate Bone

Fossil Brachiopod (Phylum Brachiopoda) — fossil

Fossil Brachiopod

Phylum Brachiopoda

Fossilized Megalodon Tooth Fragment (Otodus megalodon (Carcharocles megalodon fossil)) — sedimentary

Fossilized Megalodon Tooth Fragment

Otodus megalodon (Carcharocles megalodon fossil)

Chalcedony (Agate) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (Agate)

Silicon Dioxide (SiO2)

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

Rhodonite

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

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

Jasper

Silicon Dioxide (SiO2) with impurities

Carnelian (Carnelian (Cryptocrystalline variety of Quartz, SiO2)) — mineral

Carnelian

Carnelian (Cryptocrystalline variety of Quartz, SiO2)

Pyrite (Iron Disulfide (FeS2)) — mineral

Pyrite

Iron Disulfide (FeS2)

Pyrite (Iron Disulfide (FeS2)) — mineral

Pyrite

Iron Disulfide (FeS2)

Pyrite (Cube variety) (Iron Sulfide (FeS2)) — mineral

Pyrite (Cube variety)

Iron Sulfide (FeS2)

Fossil bivalve shell (Fossilized or partially mineralized bivalve; exact genus cannot be determined from the image) — fossil

Fossil bivalve shell

Fossilized or partially mineralized bivalve; exact genus cannot be determined from the image

Fossilized Bone (Permineralized Vertebrate Bone) — fossil

Fossilized Bone

Permineralized Vertebrate Bone

Fossilized Bone Chunk (likely Dinosaur or Large Mammal) (Permineralized Fossil Bone) — sedimentary

Fossilized Bone Chunk (likely Dinosaur or Large Mammal)

Permineralized Fossil Bone

Polished amber-colored stone, possibly chert or jasper (Uncertain from image; likely microcrystalline quartz (SiO₂) if chert/jasper) — mineral

Polished amber-colored stone, possibly chert or jasper

Uncertain from image; likely microcrystalline quartz (SiO₂) if chert/jasper

Galena (Lead(II) sulfide (PbS)) — mineral

Galena

Lead(II) sulfide (PbS)

Fossilized Brachiopod (Brachiopoda (Phylum)) — fossil

Fossilized Brachiopod

Brachiopoda (Phylum)

Turritella Fossil (Turritella (Class Gastropoda, Family Turritellidae)) — fossil

Turritella Fossil

Turritella (Class Gastropoda, Family Turritellidae)

Chert (with Limestone and Iron Oxide staining) (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (with Limestone and Iron Oxide staining)

Cryptocrystalline Quartz (SiO2)

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

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Fossil shark teeth (Likely fossilized shark teeth, possibly Carcharhiniformes or related sharks; exact species cannot be determined from the photo.) — fossil

Fossil shark teeth

Likely fossilized shark teeth, possibly Carcharhiniformes or related sharks; exact species cannot be determined from the photo.

Fossiliferous Flint (Microcrystalline Quartz (SiO2) with Echinoid Fossil) — sedimentary

Fossiliferous Flint

Microcrystalline Quartz (SiO2) with Echinoid Fossil

Pyrite (Fool's Gold) (Iron Sulfide (FeS2)) — mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Pyrite (Pseudomorph) (Iron Sulfide (FeS2)) — mineral

Pyrite (Pseudomorph)

Iron Sulfide (FeS2)