Rock Identifier

Category

Sedimentary (Biogenic)

Browse sedimentary (biogenic) specimens identified by the Rock Identifier community.

Chert (with Iron Staining) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (with Iron Staining)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (Grooved/Weathered) (Arenite (composed primarily of Quartz and Lithic fragments)) — sedimentary

Sandstone (Grooved/Weathered)

Arenite (composed primarily of Quartz and Lithic fragments)

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

Chert (Flint variety)

Silicon Dioxide (SiO2)

Red Jasper (Mahogany Obsidian variant similarity) (Silicon Dioxide (SiO2) with iron oxide inclusions) — sedimentary

Red Jasper (Mahogany Obsidian variant similarity)

Silicon Dioxide (SiO2) with iron oxide inclusions

Fossilized Pycnodonte Oyster (Pycnodonte (Gryphaeostrea) species; Composition is Calcium Carbonate (Calcite/Aragonite)) — sedimentary

Fossilized Pycnodonte Oyster

Pycnodonte (Gryphaeostrea) species; Composition is Calcium Carbonate (Calcite/Aragonite)

Brown Jasper (Silicon Dioxide (SiO2)) — sedimentary

Brown Jasper

Silicon Dioxide (SiO2)

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

Chert (Flint Pebbles)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Red Chert (Microcrystalline Quartz (SiO2)) — sedimentary

Red Chert

Microcrystalline Quartz (SiO2)

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

Chert (variations include Flint/Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (and Chert-based Jasper) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — Sedimentary

Chert (and Chert-based Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

Quartz Geode (likely within Limestone or Dolomite matrix) (Quartz (SiO₂)) — Mineral within a Sedimentary Rock

Quartz Geode (likely within Limestone or Dolomite matrix)

Quartz (SiO₂)

Mineral within a Sedimentary Rock

Calamites (Fossilized Horsetail) (Calamites suckowii (Family: Calamitaceae)) — sedimentary

Calamites (Fossilized Horsetail)

Calamites suckowii (Family: Calamitaceae)

Crushed Limestone (Calcium Carbonate (CaCO3)) — Sedimentary

Crushed Limestone

Calcium Carbonate (CaCO3)

Sandstone Beach Pebble (Clastic Sedimentary Rock (primarily Quartz with Iron Oxide coating)) — sedimentary

Sandstone Beach Pebble

Clastic Sedimentary Rock (primarily Quartz with Iron Oxide coating)

Sandstone (Ferruginous) (Arenite (with Iron Oxides)) — sedimentary

Sandstone (Ferruginous)

Arenite (with Iron Oxides)

Sandstone (Arenite (SiO2 + various cementing minerals)) — sedimentary

Sandstone

Arenite (SiO2 + various cementing minerals)

Chert (Grey-Green Var.) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Grey-Green Var.)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous) (Sandstone (Clastic sedimentary rock, predominantly SiO2 with Fe2O3 cement)) — sedimentary

Sandstone (Ferruginous)

Sandstone (Clastic sedimentary rock, predominantly SiO2 with Fe2O3 cement)

Fossilized Dinosaur Skull (Tyrannosaurus rex) (Tyrannosaurus rex (permineralized fossil), rich in Hydroxylapatite/Silica) — sedimentary

Fossilized Dinosaur Skull (Tyrannosaurus rex)

Tyrannosaurus rex (permineralized fossil), rich in Hydroxylapatite/Silica

Fossiliferous Limestone (Bivalve Fossil) (Calcium Carbonate (CaCO3) with Bivalvia fossil) — sedimentary

Fossiliferous Limestone (Bivalve Fossil)

Calcium Carbonate (CaCO3) with Bivalvia fossil

Sandstone (with Manganese staining) (Arenite (composed primarily of SiO2)) — sedimentary

Sandstone (with Manganese staining)

Arenite (composed primarily of SiO2)

Limestone Pebble (Calcium Carbonate (CaCO3)) — sedimentary

Limestone Pebble

Calcium Carbonate (CaCO3)

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

Chert (Septarian or Nodular variety)

Microcrystalline Quartz (SiO2)

Limonite (Yellow Ochre) (Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)) — mineral

Limonite (Yellow Ochre)

Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)

Petrified Wood (Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)) — metamorphic

Petrified Wood

Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)

Quartzite (Metamorphosed Quartz Sandstone (SiO2)) — metamorphic

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Carnelian (Carnelian (SiO2 with Iron Oxide impurities)) — mineral

Carnelian

Carnelian (SiO2 with Iron Oxide impurities)

Banded Slate or Siltstone with Quartz/Calcite Veins (Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)) — metamorphic

Banded Slate or Siltstone with Quartz/Calcite Veins

Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)

Quartzite River Stone (Quartzite (primarily SiO2)) — metamorphic

Quartzite River Stone

Quartzite (primarily SiO2)

Precious Opal (Hydrated amorphous silica (SiO2·nH2O)) — mineral

Precious Opal

Hydrated amorphous silica (SiO2·nH2O)

Fossilized Shark Tooth (Otodus obliquus) (Otodus obliquus (composed primarily of Fluorapatite)) — mineral

Fossilized Shark Tooth (Otodus obliquus)

Otodus obliquus (composed primarily of Fluorapatite)

Hematite / Goethite (Iron Ore) (Iron Oxide (Fe2O3 / FeO(OH))) — mineral

Hematite / Goethite (Iron Ore)

Iron Oxide (Fe2O3 / FeO(OH))

Rhodochrosite (Manganese carbonate (MnCO3)) — mineral

Rhodochrosite

Manganese carbonate (MnCO3)

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

Chert (Flint)

Microcrystalline Quartz (SiO2)

Pyrite on Limestone (Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix) — sedimentary (matrix) / mineral (inclusion)

Pyrite on Limestone

Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix

sedimentary (matrix) / mineral (inclusion)

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

Chert (Flint)

Chert (SiO2)

Chalcedony on Matrix (Silicon Dioxide (SiO2)) — mineral

Chalcedony on Matrix

Silicon Dioxide (SiO2)

Hematite (Hematite (Iron(III) oxide, Fe2O3)) — mineral

Hematite

Hematite (Iron(III) oxide, Fe2O3)

Banded Calcite (often sold as Caribbean Calcite or Mexican Onyx) (Calcium Carbonate (CaCO3)) — mineral

Banded Calcite (often sold as Caribbean Calcite or Mexican Onyx)

Calcium Carbonate (CaCO3)

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

Chert (Flint)

Microcrystalline Quartz (SiO2)

Quartz (Smoky/Grey variety) (Silicon Dioxide (SiO2)) — mineral

Quartz (Smoky/Grey variety)

Silicon Dioxide (SiO2)