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

Schist (N/A (a rock type, not a mineral formula)) — metamorphic

Schist

N/A (a rock type, not a mineral formula)

Chert (Common Opal/Jasper variety) (Microcrystalline Quartz (SiO2) with hydration) — sedimentary

Chert (Common Opal/Jasper variety)

Microcrystalline Quartz (SiO2) with hydration

Concretionary Sandstone (Clastic Sedimentary Rock (Sandstone with secondary mineral cementation)) — sedimentary

Concretionary Sandstone

Clastic Sedimentary Rock (Sandstone with secondary mineral cementation)

Moss Agate (Silicon Dioxide (SiO2) with inclusions) — mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions

Likely pyrite-bearing rock fragment (Pyrite, FeS₂, possibly in a dark host rock) — mineral

Likely pyrite-bearing rock fragment

Pyrite, FeS₂, possibly in a dark host rock

Chert (River Pebble) (Silicon Dioxide (SiO2)) — sedimentary

Chert (River Pebble)

Silicon Dioxide (SiO2)

Fossiliferous Sandstone / Fossil Fragment (Fossiliferous Sedimentary Matrix with Indeterminate Fossil Material) — fossil

Fossiliferous Sandstone / Fossil Fragment

Fossiliferous Sedimentary Matrix with Indeterminate Fossil Material

River Stone (likely Mudstone or Siltstone) (Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)) — sedimentary

River Stone (likely Mudstone or Siltstone)

Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)

Glauconitic Sandstone (Greensand) (Glauconitic Quartz Arenite (containing Glauconite, (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)) — sedimentary

Glauconitic Sandstone (Greensand)

Glauconitic Quartz Arenite (containing Glauconite, (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)

Petrified Wood (Silicified Wood (primarily Chalcedony or Quartz, SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily Chalcedony or Quartz, SiO2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood (Silicified wood (primarily Quartz, SiO2)) — fossil

Petrified Wood

Silicified wood (primarily Quartz, SiO2)

Petrified Wood (Silicified wood (primarily Silicon Dioxide, SiO2)) — metamorphic

Petrified Wood

Silicified wood (primarily Silicon Dioxide, SiO2)

Chert (Septarian or Nodular variety) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Septarian or Nodular variety)

Microcrystalline Quartz (SiO2)

Chert / Jasper (Cryptocrystalline Silica (SiO2)) — sedimentary

Chert / Jasper

Cryptocrystalline Silica (SiO2)

Glauconite (Green Sandstone) (Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2) — sedimentary

Glauconite (Green Sandstone)

Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2

Polished plume agate (Chalcedony (microcrystalline SiO₂) with iron-oxide inclusions) — mineral

Polished plume agate

Chalcedony (microcrystalline SiO₂) with iron-oxide inclusions

Chert (Flint Pebbles) (Chert (SiO2)) — sedimentary

Chert (Flint Pebbles)

Chert (SiO2)

Chert (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert

Cryptocrystalline Quartz (SiO2)

Sandstone Pebble (Arenite (primarily SiO2)) — sedimentary

Sandstone Pebble

Arenite (primarily SiO2)

Petrified Wood (Silicified Wood (SiO2)) — metamorphic

Petrified Wood

Silicified Wood (SiO2)

Fossiliferous Limestone (Crinoid stem) (CaCO3 (Calcium Carbonate) with Fossil Inclusions) — sedimentary

Fossiliferous Limestone (Crinoid stem)

CaCO3 (Calcium Carbonate) with Fossil Inclusions

Slate (Slate (foliated metamorphic rock, primarily composed of quartz, illite, chlorite, and micas)) — metamorphic

Slate

Slate (foliated metamorphic rock, primarily composed of quartz, illite, chlorite, and micas)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Fossiliferous Limestone (Sedimentary Calcium Carbonate (CaCO3)) — sedimentary

Fossiliferous Limestone

Sedimentary Calcium Carbonate (CaCO3)

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

Fossil bivalve shell (Likely an extinct or modern-like ribbed cockle/scallop; exact genus requires locality and diagnostic hinge features) — fossil

Fossil bivalve shell

Likely an extinct or modern-like ribbed cockle/scallop; exact genus requires locality and diagnostic hinge features

Banded Chert (River Siltstone) (Microcrystalline Quartz (SiO2)) — sedimentary

Banded Chert (River Siltstone)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variation) (Chert (SiO2)) — sedimentary

Chert (Jasper/Flint variation)

Chert (SiO2)

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

Chert (Quartz Variety)

Chert (mostly SiO2 / Silicon Dioxide)

Chert (Field Stone) (Microcrystalline / Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Field Stone)

Microcrystalline / Cryptocrystalline Quartz (SiO2)

Chert (or Microcrystalline Quartz) (Chert (Silicon Dioxide, SiO2)) — sedimentary

Chert (or Microcrystalline Quartz)

Chert (Silicon Dioxide, SiO2)

Fossiliferous Limestone (Limestone (CaCO3 with Bioclasts)) — sedimentary

Fossiliferous Limestone

Limestone (CaCO3 with Bioclasts)

Chert (Nodular) (Microcrystalline Silica (SiO2)) — sedimentary

Chert (Nodular)

Microcrystalline Silica (SiO2)

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

Chert (Flint)

Chert (Silicon Dioxide, SiO2)

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

Petrified Wood (Black / Carbonized)

Silicon Dioxide (Quartz/Chalcedony replacing Organic Matter)

Limestone (River Pebble) (Calcium Carbonate (CaCO3)) — sedimentary

Limestone (River Pebble)

Calcium Carbonate (CaCO3)

Calcareous Tufa (Tufa) (Precipitated Calcium Carbonate (CaCO3)) — sedimentary

Calcareous Tufa (Tufa)

Precipitated Calcium Carbonate (CaCO3)

Tumbled black stone, likely black agate or onyx (Microcrystalline quartz (SiO₂), probably chalcedony/black agate; exact identification requires testing) — mineral

Tumbled black stone, likely black agate or onyx

Microcrystalline quartz (SiO₂), probably chalcedony/black agate; exact identification requires testing

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

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (often called Jasper or River Rock) (Chert (SiO2)) — sedimentary

Chert (often called Jasper or River Rock)

Chert (SiO2)

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

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)