Rock Identifier

Category

Organic (Geological Interest)

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

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

Chert (Black Flint)

Silicon Dioxide (SiO2)

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

Chert (Nodule)

Microcrystalline Quartz (SiO2)

Chert (specifically Flint) (Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)) — sedimentary

Chert (specifically Flint)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

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

Chert (and Limestone)

Silicon Dioxide (SiO2)

Chert (and Flint) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Chert (and Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

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

Chert (Nodule)

Chert (Microcrystalline Quartz, SiO2)

Chert (Flint) (Cryptocrystalline quartz (SiO2)) — sedimentary

Chert (Flint)

Cryptocrystalline quartz (SiO2)

Coal (Bituminous Coal / Anthracite) — sedimentary

Coal

Bituminous Coal / Anthracite

Coal (most likely Bituminous or Anthracite) (Coal (organic sedimentary rock)) — Sedimentary

Coal (most likely Bituminous or Anthracite)

Coal (organic sedimentary rock)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Sandstone Concretion (Sedimentary Clastic Rock (Silicate-rich)) — sedimentary

Sandstone Concretion

Sedimentary Clastic Rock (Silicate-rich)

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

Chert (Jasper variation)

Microcrystalline Quartz (SiO2)

Chert (specifically Flint Arrowhead) (Silicon dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Chert (specifically Flint Arrowhead)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Quartzite Pebble with Pyrite Coating (SiO2 (Quartz) with FeS2 (Pyrite) inclusions or surface coating) — metamorphic

Quartzite Pebble with Pyrite Coating

SiO2 (Quartz) with FeS2 (Pyrite) inclusions or surface coating

Concrete or asphalt-like aggregate surface with a dark fragment (Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock) — sedimentary

Concrete or asphalt-like aggregate surface with a dark fragment

Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock

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

Chert (Pink Jasper)

Microcrystalline Quartz (SiO2)

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

Glauconite sand

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

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

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

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (Jasper/Mudstone variety with Oxidation) (Silicon dioxide (SiO2)) — sedimentary

Chert (Jasper/Mudstone variety with Oxidation)

Silicon dioxide (SiO2)

Ironstone Concretion / Limonite Node (Goethite and Limonite (FeO(OH) nH2O)) — sedimentary

Ironstone Concretion / Limonite Node

Goethite and Limonite (FeO(OH) nH2O)

Coral Fossil (Agatized Coral or Petoskey Stone) (Hexagonaria percarinata (if Petoskey) or generally Scleractinia (Agatized Coral)) — Sedimentary/Fossil

Coral Fossil (Agatized Coral or Petoskey Stone)

Hexagonaria percarinata (if Petoskey) or generally Scleractinia (Agatized Coral)

Sedimentary/Fossil

Petrified Wood (Silicified Wood (primarily Quartz/Chalcedony, formula: SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula: SiO2)

Limestone (Sedimentary Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Glauconitic Sandstone (Greensand) (Glauconitic quartz wacke or arenite) — sedimentary

Glauconitic Sandstone (Greensand)

Glauconitic quartz wacke or arenite

Petrified Wood (Silicified Wood (SiO2)) — metamorphic

Petrified Wood

Silicified Wood (SiO2)

Pink shell fragment (Calcium carbonate, likely aragonite or calcite (CaCO₃); probably a bivalve or gastropod shell fragment) — fossil

Pink shell fragment

Calcium carbonate, likely aragonite or calcite (CaCO₃); probably a bivalve or gastropod shell fragment

Pearl (Aragonite / Calcium Carbonate (CaCO3)) — mineral

Pearl

Aragonite / Calcium Carbonate (CaCO3)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Limestone (or Sandstone) (Calcium Carbonate (CaCO3) / Silica (SiO2)) — sedimentary

Limestone (or Sandstone)

Calcium Carbonate (CaCO3) / Silica (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Limestone Concretion (Botryoidal/Calcareous Nodules) (Calcium Carbonate Concretion (CaCO3)) — sedimentary

Limestone Concretion (Botryoidal/Calcareous Nodules)

Calcium Carbonate Concretion (CaCO3)

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

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with inclusions

Petrified Wood (Silicified Wood (SiO2)) — mineral

Petrified Wood

Silicified Wood (SiO2)

Pearl (Nacre (aragonite, CaCO₃, in a conchiolin matrix)) — gemstone

Pearl

Nacre (aragonite, CaCO₃, in a conchiolin matrix)

Fossilized Fish Skeleton in Matrix (Vertebrata (Class: Actinopterygii), typically found in limestone or shale matrices) — sedimentary

Fossilized Fish Skeleton in Matrix

Vertebrata (Class: Actinopterygii), typically found in limestone or shale matrices

Geode with Quartz Crystal Cavity (Silicon Dioxide (SiO2) in Calcareous/Siliceous Matrix) — sedimentary

Geode with Quartz Crystal Cavity

Silicon Dioxide (SiO2) in Calcareous/Siliceous Matrix

Glauconitic Sandstone (Glauconitic Quartz Arenite) — sedimentary

Glauconitic Sandstone

Glauconitic Quartz Arenite

Banded Chert with Quartz Veining (Microcrystalline Quartz (SiO2)) — sedimentary

Banded Chert with Quartz Veining

Microcrystalline Quartz (SiO2)

Cultured pearls (Pearl; predominantly aragonite (CaCO₃) in nacre with organic conchiolin) — gemstone

Cultured pearls

Pearl; predominantly aragonite (CaCO₃) in nacre with organic conchiolin

Quartz with Iron Stains (Quartz (SiO2) with iron oxide/hydroxide staining) — Mineral

Quartz with Iron Stains

Quartz (SiO2) with iron oxide/hydroxide staining

Septarian Nodule (Micro-fragment) (Septarian Nodule / Concretion (CaCO3 + CaMg(CO3)2 + Quartz)) — sedimentary

Septarian Nodule (Micro-fragment)

Septarian Nodule / Concretion (CaCO3 + CaMg(CO3)2 + Quartz)