Rock Identifier

Category

Sedimentary (Biogenic)

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

Howlite (Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)) — mineral

Howlite

Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)

Aventurine (Silicon Dioxide (SiO2) with inclusions of Fuchsite mica) — metamorphic

Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite mica

Angelite (Anhydrite (Calcium Sulfate, CaSO4)) — mineral

Angelite

Anhydrite (Calcium Sulfate, CaSO4)

Garnet (Almandine) (Almandine (Fe3Al2(SiO4)3)) — metamorphic

Garnet (Almandine)

Almandine (Fe3Al2(SiO4)3)

Marble (Recrystallized Calcite (CaCO3) Rock) — metamorphic

Marble

Recrystallized Calcite (CaCO3) Rock

Marble (Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)) — metamorphic

Marble

Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)

Bumblebee Jasper (Calcite with Arsenic and Manganese oxides (technically a volcanic rock)) — igneous

Bumblebee Jasper

Calcite with Arsenic and Manganese oxides (technically a volcanic rock)

Chert (often called Flint) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pyrite (Fool's Gold) (Iron Sulfide (FeS2)) — mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Calcite (Iceland Spar) (Calcite (Calcium Carbonate, CaCO3)) — mineral

Calcite (Iceland Spar)

Calcite (Calcium Carbonate, CaCO3)

Pyrite (Fool's Gold) (Iron Disulfide (FeS2)) — mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Chalcedony (Common Opal variant or Quartz) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (Common Opal variant or Quartz)

Silicon Dioxide (SiO2)

Petrified Wood (Silicified wood (Quartz/Chalcedony replacement of organic matter)) — sedimentary

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement of organic matter)

Chert (Tan/Yellow variety) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Tan/Yellow variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Red Sandstone (Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)) — sedimentary

Red Sandstone

Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Crinoid Fossil in Limestone (Class Crinoidea in Carbonate Matrix (CaCO3)) — sedimentary

Crinoid Fossil in Limestone

Class Crinoidea in Carbonate Matrix (CaCO3)

Red Sandstone (Clastic Terrigenous Sedimentary Rock (typically Hematitic Quartz Arenite or Arkose)) — sedimentary

Red Sandstone

Clastic Terrigenous Sedimentary Rock (typically Hematitic Quartz Arenite or Arkose)

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

Chert (and Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

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

Chert (White Chert/Flint)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

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

Petrified Wood

Silicified Wood (primarily SiO2)

Siltstone (Siltstone (primarily SiO2 with Al2O3)) — sedimentary

Siltstone

Siltstone (primarily SiO2 with Al2O3)

Chert (Commonly known as Flint or Jasper when pigmented) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Commonly known as Flint or Jasper when pigmented)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Limonite (Ironstone Concretion) (Limonite (Hydrous ferric oxide mixture, FeO(OH)·nH2O)) — sedimentary

Limonite (Ironstone Concretion)

Limonite (Hydrous ferric oxide mixture, FeO(OH)·nH2O)

Chert (Jasper) (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Jasper)

Cryptocrystalline Quartz (SiO2)

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

Chert (Red Jasper)

Microcrystalline Quartz (SiO2)

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

Chert (and Limestone)

Silicon Dioxide (SiO2)

Chert (often called Flint for dark variants) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint for dark variants)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Red Sandstone (Arenite (Ferruginous Sandstone)) — sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Siltstone (Siltstone) — sedimentary

Siltstone

Siltstone

Chert (White-Tan variety) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (White-Tan variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Limonite and Goethite encrusted Chert/Ironstone (Hydrated Iron Oxide (FeO(OH)·nH2O) with cryptocrystalline Silica (SiO2)) — sedimentary

Limonite and Goethite encrusted Chert/Ironstone

Hydrated Iron Oxide (FeO(OH)·nH2O) with cryptocrystalline Silica (SiO2)

Jasper (likely Brown or Brecciated) (Jasper (Silicon Dioxide, SiO2)) — sedimentary

Jasper (likely Brown or Brecciated)

Jasper (Silicon Dioxide, SiO2)

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

Geode with Quartz and Chalcedony (Silicon Dioxide (SiO2)) — sedimentary

Geode with Quartz and Chalcedony

Silicon Dioxide (SiO2)

Sandstone (Ferruginous) (Arenite with Iron Oxide cement (SiO2 + Fe2O3)) — sedimentary

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Limonitic Sandstone with Inclusion (Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)) — sedimentary

Limonitic Sandstone with Inclusion

Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)

Sandstone (Yellow/Tan) (Clastic sedimentary rock (primarily SiO2 with iron oxide staining)) — sedimentary

Sandstone (Yellow/Tan)

Clastic sedimentary rock (primarily SiO2 with iron oxide staining)

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

Chert

Chert (Microcrystalline Silica, SiO2)

Shale or Siltstone (Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)) — sedimentary

Shale or Siltstone

Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)