Sandstone
Arenite (composed of SiO2, CaCO3, or iron oxides)
Category
Browse sedimentary (fossilized organic remain) specimens identified by the Rock Identifier community.
Sandstone
Arenite (composed of SiO2, CaCO3, or iron oxides)
Chert (Jasper/Mudstone variant)
Silicon Dioxide (SiO2)
Likely amber or amber-like resin fragment
Amber (fossilized plant resin), commonly succinite; identification uncertain from the image
Ferruginous Siltstone or Mudstone
Ferruginous Siltstone / Goethitic Sandstone
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Sandstone
Arenite (SiO2 primarily)
Sandstone
Arenite (SiO2 based)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Iron Oxide staining)
Ferruginous Sandstone (with ripple marks)
Arenite with Iron-Oxide (Fe2O3) cement
Sandstone
Arenite (Secondary classification based on grain size)
Sandstone
Arenite (SiO2 primarily)
Sandstone
Arenite (SiO2 primarily)
Sandstone
Arenite (SiO2 principal)
Silicified oyster fossil
Fossil oyster shell, commonly Ostrea or Crassostrea, replaced or encrusted by chalcedony/quartz
Banded Iron Formation (BIF)
Banded Iron Formation (Magnetite/Hematite and Chert)
Fossil Sea Urchin / Echinoid
Class Echinoidea
Tumbled brown stone, possibly amber or polished agate
Indeterminate from image; possibilities include amber (fossilized plant resin, organic) or chalcedony/quartz (SiO₂)
Limestone (Flagstone)
Fossiliferous Limestone (CaCO3)
Ammonite Fossil
Ammonoidea (typically preserved as Calcite or Aragonite)
Dinosaur Claw (Dromaeosaurid)
Dromaeosaurid ungual (potential Deinonychus or Velociraptorine)
Petoskey Stone (Fossilized Coral)
Hexagonaria percarinata
Amber-bearing Coal/Sedimentary Rock
Bituminous coal or carbonaceous siltstone with Fossilized Tree Resin (C10H16O)
Likely quartzite
Quartzite, composed predominantly of quartz (SiO₂)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Sedimentary Strata of the Badlands (Mudstone, Siltstone, and Sandstone)
White River Group (Brule and Chadron Formations)
Crinoidal Limestone
Bioclastic Limestone
Pearl
Calcium Carbonate (CaCO3) with Conchiolin
Pyrite
Iron Sulfide (FeS2)
Chert Nodules with Iron Staining
Microcrystalline Quartz (SiO2)
Mammoth Tooth Fragment
Mammuthus primigenius (fossilized dentin and enamel)
Polished amber
Fossilized tree resin; chiefly polymerized diterpenoid resin (succinite when Baltic-type)
Fossilized Coral (Petoskey Stone / Chain Coral)
Scleractinia (Order) / Halysites (Genus for Chain Coral types)
Fossilized Shell Fragment
Bivalvia or Gastropoda (Class) fragment
Mookaite Jasper
Silicified Radiolarite (SiO2)
Sandstone
Sedimentary Rock (Quartz arenite)
Sandstone
Sedimentary Rock (Quartz arenite)
Crinoid Fossil in Limestone
Crinoidea (Phylum Echinodermata) in Calcite Matrix (CaCO3)
Chert (Jasper/Brown Chert)
Silicon Dioxide (SiO2)
Trilobite Pygidium (Tail Segment)
Phylum Arthropoda, Class Trilobita (likely order Phacopida)
Quartz Conglomerate
Quartz Conglomerate (clastic sedimentary rock)