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)

Chert (Nodule) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Chert (Nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartz Geode (Silicon Dioxide (SiO2)) — mineral

Quartz Geode

Silicon Dioxide (SiO2)

Blue Celestite (Celestine) (Strontium sulfate (SrSO4)) — mineral

Blue Celestite (Celestine)

Strontium sulfate (SrSO4)

Quartz Crystal Fragment (Silicon Dioxide (SiO2)) — mineral

Quartz Crystal Fragment

Silicon Dioxide (SiO2)

Satin Spar (often sold as Selenite) (Gypsum (CaSO4·2H2O)) — mineral

Satin Spar (often sold as Selenite)

Gypsum (CaSO4·2H2O)

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

Garnet (specifically Almandine)

Almandine - Fe3Al2(SiO4)3

Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur). (Galena (PbS)) — mineral

Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).

Galena (PbS)

Satin Spar (Gypsum) (Hydrous Calcium Sulfate (CaSO4·2H2O)) — mineral

Satin Spar (Gypsum)

Hydrous Calcium Sulfate (CaSO4·2H2O)

Zoisite with Ruby (Anyolite (Calcium aluminum hydroxy silicate with Corundum) Ca2Al3(SiO4)3(OH)) — metamorphic

Zoisite with Ruby

Anyolite (Calcium aluminum hydroxy silicate with Corundum) Ca2Al3(SiO4)3(OH)

Sandstone (Clastic sedimentary rock (primarily SiO2)) — sedimentary

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone (Arenite (SiO2 based)) — sedimentary

Sandstone

Arenite (SiO2 based)

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

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

Chert / Red Jasper

Microcrystalline Quartz (SiO2)

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

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Limonite Sandstone (Ferruginous Sandstone (Hydrated Iron Oxide)) — sedimentary

Limonite Sandstone

Ferruginous Sandstone (Hydrated Iron Oxide)

Glauconite ((K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2) — mineral

Glauconite

(K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2

Ammonite Fossil (Ammonoidea (primarily composed of Calcite, CaCO3)) — sedimentary

Ammonite Fossil

Ammonoidea (primarily composed of Calcite, CaCO3)

Sandstone (with Iron Staining) (Clastic Sedimentary Rock (primarily Quartz, SiO2)) — sedimentary

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily Quartz, SiO2)

Sandstone (Quartz Arenite) (Clastic Sedimentary Rock - Quartz Arenite) — sedimentary

Sandstone (Quartz Arenite)

Clastic Sedimentary Rock - Quartz Arenite

Sandstone (likely Quartzose type) (Clastic sedimentary rock (primarily SiO2)) — sedimentary

Sandstone (likely Quartzose type)

Clastic sedimentary rock (primarily SiO2)

Sandstone (Graywacke type) (Clastic Sedimentary Rock (Lithic Sandstone)) — sedimentary

Sandstone (Graywacke type)

Clastic Sedimentary Rock (Lithic Sandstone)

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

Sandstone (Arenite) — sedimentary

Sandstone

Arenite

Sandstone (Arenite) — sedimentary

Sandstone

Arenite

Jasper Chert Nodules (Silicon Dioxide (SiO2) with Hematite impurities) — sedimentary

Jasper Chert Nodules

Silicon Dioxide (SiO2) with Hematite impurities

Banded Iron Formation (Banded Iron Formation (BIF)) — sedimentary

Banded Iron Formation

Banded Iron Formation (BIF)

Marble (Marble (metamorphosed limestone or dolostone), primarily composed of calcite (CaCO3) or dolomite (CaMg(CO3)2)) — metamorphic

Marble

Marble (metamorphosed limestone or dolostone), primarily composed of calcite (CaCO3) or dolomite (CaMg(CO3)2)

Shale (possibly) (Shale (fine-grained clastic sedimentary rock)) — sedimentary

Shale (possibly)

Shale (fine-grained clastic sedimentary rock)

Sandstone (Ferruginous) (Arenite (Fe-rich)) — sedimentary

Sandstone (Ferruginous)

Arenite (Fe-rich)

Sandstone (Sandstone (lithified quartz arenite, arkose, graywacke, etc. depending on composition)) — Sedimentary Rock

Sandstone

Sandstone (lithified quartz arenite, arkose, graywacke, etc. depending on composition)

Sedimentary Rock

Chert (Flint variety) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Flint variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Red Sandstone (Arenite (Fe2O3 rich)) — sedimentary

Red Sandstone

Arenite (Fe2O3 rich)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — metamorphic

Petrified Wood

Silicified Wood (SiO2)

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

Chert (variations include Flint or Jasper)

Cryptocrystalline Quartz (SiO2)

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

Chert (Nodule)

Microcrystalline quartz (SiO2)

Limonite Pseudomorph after Pyrite (Limonite (Hydrous iron oxides e.g., FeO(OH)·nH2O) pseudomorphing Pyrite (FeS2)) — mineral

Limonite Pseudomorph after Pyrite

Limonite (Hydrous iron oxides e.g., FeO(OH)·nH2O) pseudomorphing Pyrite (FeS2)

Banded Chert (Microcrystalline Quartz (SiO2)) — sedimentary

Banded Chert

Microcrystalline Quartz (SiO2)

Sandstone (Micaceous Sandstone) (Arenite (SiO2 with KAl2(AlSi3O10)(OH)2 inclusions)) — sedimentary

Sandstone (Micaceous Sandstone)

Arenite (SiO2 with KAl2(AlSi3O10)(OH)2 inclusions)

Sandstone (likely Fossiliferous) (Arenite / Sedimentum arenaceum) — sedimentary

Sandstone (likely Fossiliferous)

Arenite / Sedimentum arenaceum

Chert (River Cobble) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (River Cobble)

Microcrystalline or cryptocrystalline Quartz (SiO2)