Rock Identifier

Category

Organic (Geological Relative)

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

Petrified Wood (Silicified Wood (primarily SiO₂ / Silicon Dioxide)) — mineral

Petrified Wood

Silicified Wood (primarily SiO₂ / Silicon Dioxide)

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

Petrified Wood

Silicified Wood (SiO2)

sedimentary
Weathered chert or silicified limestone (Microcrystalline quartz (SiO₂), likely chert formed by silicification of carbonate rock) — sedimentary

Weathered chert or silicified limestone

Microcrystalline quartz (SiO₂), likely chert formed by silicification of carbonate rock

sedimentary
Chert (specifically a fragment with Desert Varnish) (Microcrystalline quartz (SiO2)) — sedimentary

Chert (specifically a fragment with Desert Varnish)

Microcrystalline quartz (SiO2)

sedimentary
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)

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

Petrified Wood

Silicified Wood (SiO2)

sedimentary
Chert (variations include Flint or Jasper) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (variations include Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

sedimentary
Tumbled yellow calcite (Calcite (CaCO₃), likely honey or lemon calcite) — mineral

Tumbled yellow calcite

Calcite (CaCO₃), likely honey or lemon calcite

mineral
Possible flint or black chert (Microcrystalline quartz (SiO₂), likely chert/flint) — sedimentary

Possible flint or black chert

Microcrystalline quartz (SiO₂), likely chert/flint

sedimentary
Fossilized coral (likely honeycomb or branching coral) (Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃) — fossil

Fossilized coral (likely honeycomb or branching coral)

Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃

fossil
Moss Agate (Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides) — mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides

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

Petrified Wood

Silicified Wood (SiO2)

sedimentary
Shale (with minor calcite veining) (Clastic sedimentary rock (primarily clay minerals and quartz)) — sedimentary

Shale (with minor calcite veining)

Clastic sedimentary rock (primarily clay minerals and quartz)

sedimentary
Picture Jasper (Silicon Dioxide (SiO2) with iron oxide and organic impurities) — sedimentary

Picture Jasper

Silicon Dioxide (SiO2) with iron oxide and organic impurities

sedimentary
Chert (Cherty Shale / Flint) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Cherty Shale / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

sedimentary
Banded Sedimentary Rock (Siltstone/Mudstone with concretion) (Siltstone with Ferruginous Banding) — sedimentary

Banded Sedimentary Rock (Siltstone/Mudstone with concretion)

Siltstone with Ferruginous Banding

sedimentary
Aquamarine (Beryl (Be3Al2Si6O18)) — Mineral

Aquamarine

Beryl (Be3Al2Si6O18)

Mineral
Larimar (Pectolite (a blue variety of Pectolite)) — Mineral

Larimar

Pectolite (a blue variety of Pectolite)

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

Chert Nodule

Microcrystalline Quartz (SiO2)

sedimentary
Iron Ore / Hematite / Ironstone Nodule (Hematite / Goethite (Fe2O3 / FeO(OH))) — sedimentary

Iron Ore / Hematite / Ironstone Nodule

Hematite / Goethite (Fe2O3 / FeO(OH))

sedimentary
Septarian Nodule or Mud Crack Fossil (Septarian Nodule (Concretion)) — sedimentary

Septarian Nodule or Mud Crack Fossil

Septarian Nodule (Concretion)

sedimentary
Green Moss Agate (Agate (Silicon Dioxide - SiO2) with inclusions of hornblende or chlorite) — mineral

Green Moss Agate

Agate (Silicon Dioxide - SiO2) with inclusions of hornblende or chlorite

mineral
Greenschist (Greenschist facies rock) — Metamorphic

Greenschist

Greenschist facies rock

Metamorphic
Chert Nodule in Limestone (Flint in Chalk) (SiO2 (Microcrystalline Quartz) in CaCO3 (Calcite)) — sedimentary

Chert Nodule in Limestone (Flint in Chalk)

SiO2 (Microcrystalline Quartz) in CaCO3 (Calcite)

sedimentary
Banded sandstone pebble (Lithified quartz–feldspar sandstone, likely ferruginous and carbonaceous laminae) — sedimentary

Banded sandstone pebble

Lithified quartz–feldspar sandstone, likely ferruginous and carbonaceous laminae

sedimentary
Grey and White Chert (Flint) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Grey and White Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

sedimentary
Jasper (Red-Brown) (Silicon Dioxide (SiO2) with Iron Oxide impurities) — sedimentary

Jasper (Red-Brown)

Silicon Dioxide (SiO2) with Iron Oxide impurities

sedimentary
Chert (Quartz Variety) (Microcrystalline Silica (SiO2)) — sedimentary

Chert (Quartz Variety)

Microcrystalline Silica (SiO2)

sedimentary
Chert (specifically Tan/Yellow Chert) (Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)) — sedimentary

Chert (specifically Tan/Yellow Chert)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

sedimentary
Banded Calcite or Travertine (Calcium Carbonate (CaCO3)) — Sedimentary

Banded Calcite or Travertine

Calcium Carbonate (CaCO3)

Sedimentary
Petrified Wood (Silicified Wood (primarily SiO2)) — fossil

Petrified Wood

Silicified Wood (primarily SiO2)

fossil
Fossil Brachiopod (Phylum Brachiopoda) — fossil

Fossil Brachiopod

Phylum Brachiopoda

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

Petrified Wood

Silicified Wood (primarily SiO2)

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

Chert Nodule

Microcrystalline Quartz (SiO2)

sedimentary
Peridot and Citrine Gemstones (in a ring setting) (Peridot (Olivine: (Mg,Fe)2SiO4), Citrine (Quartz: SiO2)) — mineral

Peridot and Citrine Gemstones (in a ring setting)

Peridot (Olivine: (Mg,Fe)2SiO4), Citrine (Quartz: SiO2)

mineral
Weathered gray-green rock fragment (Likely shale or mudstone; exact identification requires testing) — sedimentary

Weathered gray-green rock fragment

Likely shale or mudstone; exact identification requires testing

sedimentary
Silty Shale or Mudstone (Siltstone/Mudstone (Clastic Sedimentary Rock)) — sedimentary

Silty Shale or Mudstone

Siltstone/Mudstone (Clastic Sedimentary Rock)

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

Petrified Wood

Silicified Wood (primarily SiO2)

sedimentary
Fossil Coral (Phylum Cnidaria / Rugosa or Tabulata) — fossil

Fossil Coral

Phylum Cnidaria / Rugosa or Tabulata

fossil
Tumbled chert or flint (Microcrystalline quartz (SiO₂), likely brown chert/flint) — sedimentary

Tumbled chert or flint

Microcrystalline quartz (SiO₂), likely brown chert/flint

sedimentary
Weathered shale or mudstone (Clastic mudrock, chiefly clay minerals, quartz, and feldspar) — sedimentary

Weathered shale or mudstone

Clastic mudrock, chiefly clay minerals, quartz, and feldspar

sedimentary
Chalk (Calcium Carbonate (CaCO3)) — sedimentary

Chalk

Calcium Carbonate (CaCO3)

sedimentary