Rock Identifier

Category

Organic Specimen (Fossil)

Browse organic specimen (fossil) specimens identified by the Rock Identifier community.

Learn about Organic Specimen (Fossil) in the encyclopedia

Petrified Wood

Amber

Jet

Opalized Wood

Chert (and Limestone) (Silicon Dioxide (SiO2)) — sedimentary

Chert (and Limestone)

Silicon Dioxide (SiO2)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Green Chert (Jasper) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Green Chert (Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Pink Opal (Hydrated Silica (SiO2·nH2O)) — mineral

Pink Opal

Hydrated Silica (SiO2·nH2O)

Chalcedony in Matrix (likely Agatized Coral or Chert) (Silicon Dioxide (SiO2)) — sedimentary

Chalcedony in Matrix (likely Agatized Coral or Chert)

Silicon Dioxide (SiO2)

Chert (Jasper variety) (Silicon Dioxide (SiO2) with iron oxide impurities) — sedimentary

Chert (Jasper variety)

Silicon Dioxide (SiO2) with iron oxide impurities

Dendritic Agate (Silicon Dioxide with inclusions (SiO2 + Mn/Fe)) — mineral

Dendritic Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe)

Chert Pebble (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert Pebble

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (River Pebble) (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (River Pebble)

Cryptocrystalline Quartz (SiO2)

Chert (with small quartz vug) (Chert (SiO2)) — sedimentary

Chert (with small quartz vug)

Chert (SiO2)

Chert (Flint) Artifact (Silicon Dioxide (SiO2)) — sedimentary

Chert (Flint) Artifact

Silicon Dioxide (SiO2)

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

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Fossiliferous Limestone (Biogenic Limestone (Calcium Carbonate, CaCO3)) — sedimentary

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Chert (or Flint) (Chert (Sedimentary Cryptocrystalline Sio2)) — sedimentary

Chert (or Flint)

Chert (Sedimentary Cryptocrystalline Sio2)

Chert (specifically Flint or Jasper variant) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Flint or Jasper variant)

Microcrystalline Quartz (SiO2)

River Cobble (Sandstone) (Arenite (primarily SiO2)) — sedimentary

River Cobble (Sandstone)

Arenite (primarily SiO2)

Chert (often called Jasper or River Siltstone) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (often called Jasper or River Siltstone)

Microcrystalline Quartz (SiO2)

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

Chert (Jasper/Chalcedony)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Agate variety) (Microcrystalline quartz (SiO2)) — sedimentary

Chert (Jasper/Agate variety)

Microcrystalline quartz (SiO2)

Chert (Nodule) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Limestone (Limestone (Calcium Carbonate, CaCO3)) — sedimentary

Limestone

Limestone (Calcium Carbonate, CaCO3)

Fossilized Mosasaur Tooth (Mosasauridae (likely Prognathodon or Mosasaurus)) — fossil

Fossilized Mosasaur Tooth

Mosasauridae (likely Prognathodon or Mosasaurus)

Fossilized Rugose Coral (Horn Coral) (Order Rugosa) — fossil

Fossilized Rugose Coral (Horn Coral)

Order Rugosa

Fossilized Rugose Coral (Order Rugosa (Calcium Carbonate - CaCO3)) — sedimentary

Fossilized Rugose Coral

Order Rugosa (Calcium Carbonate - CaCO3)

Fossilized Coral (Petoskey Stone or similar) (Hexagonaria percarinata (Fossilized Rugose Coral)) — sedimentary

Fossilized Coral (Petoskey Stone or similar)

Hexagonaria percarinata (Fossilized Rugose Coral)

Chert (Jasper variety) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Chert (Jasper variety)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Brown variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Brown variety)

Silicon Dioxide (SiO2)

Chert (specifically Pink/Tan Chert) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Pink/Tan Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Quartz Variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Quartz Variety)

Silicon Dioxide (SiO2)

Chert (Jasper variation) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Chert (Jasper variation)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Fossiliferous Limestone (containing Brachiopods) (Biogenic Limestone (Calcium Carbonate, CaCO3)) — sedimentary

Fossiliferous Limestone (containing Brachiopods)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Chert (often called Flint when in chalk or limestone) (Silicon Dioxide (SiO₂)) — sedimentary

Chert (often called Flint when in chalk or limestone)

Silicon Dioxide (SiO₂)

Moss Agate (Chalcedony (Silicon Dioxide, SiO2) with dendritic inclusions) — mineral

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with dendritic inclusions

Chalcedony (Agate / Jasper Specimen) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (Agate / Jasper Specimen)

Silicon Dioxide (SiO2)

Rounded brown sandstone or weathered river cobble (Likely quartz-rich sandstone; exact identification requires a fresh surface and tests) — sedimentary

Rounded brown sandstone or weathered river cobble

Likely quartz-rich sandstone; exact identification requires a fresh surface and tests

Chert (specifically Tan Chert or Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chert (specifically Tan Chert or Flint)

Silicon Dioxide (SiO2)

Chert (Microcrystalline Silicon Dioxide (SiO2)) — sedimentary

Chert

Microcrystalline Silicon Dioxide (SiO2)

Chert (and Limestone) (Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)) — sedimentary

Chert (and Limestone)

Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)

Aragonite (Star Cluster or Twinned variety) (Aragonite (Calcium Carbonate, CaCO3)) — mineral

Aragonite (Star Cluster or Twinned variety)

Aragonite (Calcium Carbonate, CaCO3)