Rock Identifier

Category

Organic Structure (Not A Rock)

Browse organic structure (not a rock) specimens identified by the Rock Identifier community.

Learn about Organic Structure (Not A Rock) in the encyclopedia

Bituminous Shale

Bituminous Shale

Black Shale

Oil Shale

Petrified Wood

Crocodile Jasper

Crocodile Jasper

Opalized Wood

Rock Salt

Rock Gypsum

Coral Rock

Asphalt Rock

Calc-Silicate Rock

Calc-Silicate Rock

Talc-carbonate Rock

Talc-carbonate Rock

Fossiliferous Limestone Pebble (Calcite-rich Fossiliferous Marine Limestone) — fossil

Fossiliferous Limestone Pebble

Calcite-rich Fossiliferous Marine Limestone

Fossiliferous Shale Matrix (Clastic Sedimentary Rock with Brachiopod or Mollusk shell fragments) — sedimentary

Fossiliferous Shale Matrix

Clastic Sedimentary Rock with Brachiopod or Mollusk shell fragments

Chert / Pink Flint (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert / Pink Flint

Cryptocrystalline Quartz (SiO2)

Chert (Brecciated or Veined) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Brecciated or Veined)

Silicon Dioxide (SiO2)

Chert (Flint variety) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Zebra Rock / Zebra Marble (Banded Limestone-Marble Transition) — metamorphic

Zebra Rock / Zebra Marble

Banded Limestone-Marble Transition

Fossiliferous limestone / shell hash rock (Bioclastic limestone (calcarenite or coquina), dominantly CaCO₃) — sedimentary

Fossiliferous limestone / shell hash rock

Bioclastic limestone (calcarenite or coquina), dominantly CaCO₃

Petrified Wood (Black / Carbonized) (Silicon Dioxide (Quartz/Chalcedony replacing Organic Matter)) — fossil

Petrified Wood (Black / Carbonized)

Silicon Dioxide (Quartz/Chalcedony replacing Organic Matter)

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

Chert (Smooth River Stone)

Microcrystalline or cryptocrystalline Quartz (SiO2)

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

Banded Chert (with Quartz Vein)

Microcrystalline Silica (SiO2)

Moss Agate (Chalcedony (SiO2) with inclusions of hornblende or chlorite) — mineral

Moss Agate

Chalcedony (SiO2) with inclusions of hornblende or chlorite

Chert (River Siltstone/Quartzite type) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (River Siltstone/Quartzite type)

Microcrystalline Quartz (SiO2)

Limestone (Sedimentary rock composed mainly of calcite (CaCO3)) — sedimentary

Limestone

Sedimentary rock composed mainly of calcite (CaCO3)

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

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Chert (Yellow Jasper/Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2)

Flint or chert, possibly a knapped stone tool (Microcrystalline quartz (SiO₂), commonly chalcedony with possible carbonaceous impurities) — sedimentary

Flint or chert, possibly a knapped stone tool

Microcrystalline quartz (SiO₂), commonly chalcedony with possible carbonaceous impurities

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

Chert (Flint)

Microcrystalline Quartz (SiO2)

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

Fossilized Bivalve Shell

Bivalvia (Phylum Mollusca)

Ironstone Concretion / Goethite-Hematite Geode (Goethite / Hematite Concretion (Fe3O4 / FeO(OH) / Fe2O3)) — sedimentary

Ironstone Concretion / Goethite-Hematite Geode

Goethite / Hematite Concretion (Fe3O4 / FeO(OH) / Fe2O3)

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

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Fossiliferous Chert (Silicon Dioxide (SiO2) with fossil inclusions) — sedimentary

Fossiliferous Chert

Silicon Dioxide (SiO2) with fossil inclusions

Petrified Wood (Fossilized Wood (SiO2 replacing organic matter)) — fossil

Petrified Wood

Fossilized Wood (SiO2 replacing organic matter)

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

Chert (Nodule)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Green Moss Agate (Silicon Dioxide (SiO2) with Mineral Inclusions) — sedimentary

Green Moss Agate

Silicon Dioxide (SiO2) with Mineral Inclusions

Polished agate (likely plume or moss agate) (Chalcedony, microcrystalline quartz (SiO₂), with iron-oxide and possible chlorite inclusions) — mineral

Polished agate (likely plume or moss agate)

Chalcedony, microcrystalline quartz (SiO₂), with iron-oxide and possible chlorite inclusions

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Red Coral (Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.) — Organic Gemstone (not a rock or mineral in the traditional sense, but bio-mineralized material)

Red Coral

Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.

Organic Gemstone (not a rock or mineral in the traditional sense, but bio-mineralized material)

Crinoid Fossil in Limestone (Crinoid (Class Crinoidea) in Fossiliferous Limestone (CaCO3)) — sedimentary

Crinoid Fossil in Limestone

Crinoid (Class Crinoidea) in Fossiliferous Limestone (CaCO3)

Chert (and Limestone) River Cobble (Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)) — sedimentary

Chert (and Limestone) River Cobble

Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)

Veined Limestone (Sedimentary Calcite-Veined Rock (CaCO3)) — sedimentary

Veined Limestone

Sedimentary Calcite-Veined Rock (CaCO3)

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

Flint (Chert)

Silicon Dioxide (SiO2)

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

Chert (Cherty Flint/Jasper variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

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

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Sandstone (Ferruginous) (Arenite (primarily SiO2 with Fe2O3 cement)) — sedimentary

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 cement)

Petrified Wood (Silicified Wood (SiO2)) — mineral

Petrified Wood

Silicified Wood (SiO2)

Limestone with Chert or Siltstone bands (Sedimentary carbonate rock (CaCO3) often with siliceous impurities) — sedimentary

Limestone with Chert or Siltstone bands

Sedimentary carbonate rock (CaCO3) often with siliceous impurities

Sandstone with Trace Fossils (Quartz Arenite with Bioturbation (Trace Fossils)) — sedimentary

Sandstone with Trace Fossils

Quartz Arenite with Bioturbation (Trace Fossils)

Ironstone Concretion (Siderite / Hematite-bearing Sedimentary Rock) — sedimentary

Ironstone Concretion

Siderite / Hematite-bearing Sedimentary Rock

Blue Quartzite (Dyed) (Metamorphosed Quartz-rich Sandstone (SiO2 with organic dye)) — metamorphic

Blue Quartzite (Dyed)

Metamorphosed Quartz-rich Sandstone (SiO2 with organic dye)

Fossiliferous shale or slate with plant impressions (Carbonaceous mudstone/shale; possible fossil plant material (often fern-like impressions)) — fossil

Fossiliferous shale or slate with plant impressions

Carbonaceous mudstone/shale; possible fossil plant material (often fern-like impressions)

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

Chert (often called Jasper or River Siltstone)

Microcrystalline Quartz (SiO2)