Rock Identifier

Category

Organic (Anthropogenic)

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

Learn about Organic (Anthropogenic) in the encyclopedia

Sapropel

Bituminous Shale

Bituminous Shale

Black Shale

Petrified Wood

Amber

Jet

Peat

Oil Shale

Pearl

Lizard Skin Jasper

Opalized Wood

Coral Rock

Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

Chert (Tan/Grey variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Tan/Grey variety)

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variety) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (often called Flint or Jasper locally) (Chert (Microcrystalline Quartz, Formula: SiO2)) — sedimentary

Chert (often called Flint or Jasper locally)

Chert (Microcrystalline Quartz, Formula: SiO2)

Chert (Limestone-hosted Pebble) (Sedimentary Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Limestone-hosted Pebble)

Sedimentary Cryptocrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)) — Mineral/Fossil (Sedimentary context)

Petrified Wood

Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)

Mineral/Fossil (Sedimentary context)

Petrified Wood (Silicified Wood (SiO2)) — metamorphic

Petrified Wood

Silicified Wood (SiO2)

Banded sandstone pebble (Quartz-rich lithic sandstone; exact provenance and composition require testing) — sedimentary

Banded sandstone pebble

Quartz-rich lithic sandstone; exact provenance and composition require testing

Jasper (Silicon Dioxide (Microcrystalline Quartz / Chalcedony)) — sedimentary

Jasper

Silicon Dioxide (Microcrystalline Quartz / Chalcedony)

Petrified Wood / Fossilized Wood (Silicified Wood (Silicon Dioxide - SiO2)) — fossil

Petrified Wood / Fossilized Wood

Silicified Wood (Silicon Dioxide - SiO2)

Chert (often called Flint when found in chalk/limestone) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint when found in chalk/limestone)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petrified Wood (Silicified wood (Quartz replacement)) — fossil

Petrified Wood

Silicified wood (Quartz replacement)

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

Chert (Smooth River Stone) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Smooth River Stone)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

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

Red Jasper

Silicon Dioxide (SiO2) with Hematite impurities

Petrified Wood (Silicified Wood (SiO2 permineralization)) — fossil

Petrified Wood

Silicified Wood (SiO2 permineralization)

Quartz Geode (Silicon Dioxide (SiO2)) — sedimentary

Quartz Geode

Silicon Dioxide (SiO2)

Coral Fossil (Petrified Coral) (Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)) — sedimentary

Coral Fossil (Petrified Coral)

Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)

Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

Limestone with Quartz/Calcite Veins (Sedimentary Limestone (CaCO3 with SiO2 or CaCO3 intrusions)) — sedimentary

Limestone with Quartz/Calcite Veins

Sedimentary Limestone (CaCO3 with SiO2 or CaCO3 intrusions)

Jasper (specifically Yellow Jasper and Red Jasper) (Silicon Dioxide (SiO2) with iron oxide inclusions) — sedimentary

Jasper (specifically Yellow Jasper and Red Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions

Banded Chert (with Quartz Vein) (Microcrystalline Silica (SiO2)) — sedimentary

Banded Chert (with Quartz Vein)

Microcrystalline Silica (SiO2)

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

Coquina

Biogenic Limestone (Calcium Carbonate, CaCO3)

Ironstone Concretion / Hematite Nodules (Ferruginous Sedimentary Rock (primarily Hematite Fe2O3 and Goethite FeO(OH))) — sedimentary

Ironstone Concretion / Hematite Nodules

Ferruginous Sedimentary Rock (primarily Hematite Fe2O3 and Goethite FeO(OH))

Anthracite Coal (Anthracite (Carbon-rich metamorphic coal)) — metamorphic

Anthracite Coal

Anthracite (Carbon-rich metamorphic coal)

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

Chert (Weathered)

Chert (Microcrystalline Quartz, SiO2)

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

Chert (Chert Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Travertine (often colloquially called Tufa) (Chemical Sedimentary Calcium Carbonate (CaCO3)) — sedimentary

Travertine (often colloquially called Tufa)

Chemical Sedimentary Calcium Carbonate (CaCO3)

Petrified Wood (Silicified Wood (primarily SiO2 - Silicon Dioxide)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Massive Cryptocrystalline Quartz (Chert/Chalcedony Pebble) (Silicon Dioxide (SiO2)) — sedimentary

Massive Cryptocrystalline Quartz (Chert/Chalcedony Pebble)

Silicon Dioxide (SiO2)

Graphite (Graphite (Native Carbon, C)) — metamorphic

Graphite

Graphite (Native Carbon, C)

Chert (specifically Iron-stained River Cobble) (Silicon Dioxide (SiO2)) — sedimentary

Chert (specifically Iron-stained River Cobble)

Silicon Dioxide (SiO2)

Chert (Cherty Flint/Jasper variety) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Cherty Flint/Jasper variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

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

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Petrified Wood (Silicified Wood (primarily Quartz / Chalcedony: SiO2)) — metamorphic

Petrified Wood

Silicified Wood (primarily Quartz / Chalcedony: SiO2)

Chert (Nodule) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Nodule)

Silicon Dioxide (SiO2)

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

Coquina

Biogenic Limestone (Calcium Carbonate, CaCO3)

Shale (sub-type: Carbonaceous Shale) (Lutaceous Sedimentary Rock) — sedimentary

Shale (sub-type: Carbonaceous Shale)

Lutaceous Sedimentary Rock

Green Banded Chert (Agate/Jasper) (Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite) — sedimentary

Green Banded Chert (Agate/Jasper)

Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite

Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

Red Sandstone with Reduction Spot (Quartzose Sandstone with a Leach/Reduction Spot) — sedimentary

Red Sandstone with Reduction Spot

Quartzose Sandstone with a Leach/Reduction Spot