Chalk
Micrite (primarily Calcium Carbonate or CaCO3)
Category
Browse sedimentary (fossil) specimens identified by the Rock Identifier community.
Chalk
Micrite (primarily Calcium Carbonate or CaCO3)
Bituminous Coal
Organic Sedimentary Rock (composed mostly of carbon with sulfur and hydrogen)
Fossiliferous Limestone (Coquina / Shell Limestone)
CaCO3 (Calcium Carbonate)
Sandstone (likely Graywacke or Lithic Sandstone)
Arenite / Wacke (SiO2 based with lithic fragments)
Sandstone (Weathered Pebble)
Arenite (primarily SiO2)
Chert (White Chert)
Microcrystalline Quartz (SiO2)
Chert Nodule
Chert (Cryptocrystalline variety of Quartz, SiO2)
Coal (Anthracite/Bituminous)
Carbo fossilium (primarily Carbon)
Sandstone (with Manganese staining)
Arenite (composed primarily of SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Weathered quartz-rich cobble (probable quartzite or silicified rock)
Quartzite, predominantly SiO₂; exact identification is uncertain from the photograph
Chert (also known as Flint or Common Chalcedony)
Cryptocrystalline Silica (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Ironstone Concretion (Ironstone Gourd)
Limonite/Goethite Concretion (FeOO(H))
Chert (Nodule)
Silicon Dioxide (SiO2)
Calcareous Tufa / Limestone Fragment
Calcium Carbonate (CaCO3)
Fossilized Shark Tooth
Fossilized elasmobranch tooth (Apatite/Calcium Phosphate)
Limestone
Calcium Carbonate (CaCO3)
Sandstone (specifically Arkose or Ferruginous Sandstone)
Sandstone (SiO2 predominant)
Chert / Flint
Microcrystalline Silica (SiO2)
Fossilized cylindrical shell or bone fragment
Indeterminate biogenic carbonate or phosphatic fossil; possible fragment of a tubular shell (e.g., scaphopod) or hollow bone
River Pebble (Quartz/Chert)
Silicon Dioxide (SiO2)
Sandstone (Quartzose)
Arenite (primarily SiO2)
Sandstone (Ferruginous)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 cement)
Limestone
Limestone (Calcium Carbonate - CaCO3)
Limestone
Calcium Carbonate (CaCO3)
Sandstone with Vitrinite/Coal inclusions
Arenite with Carbonaceous inclusions
River Cobble (Conglomerate context)
Unconsolidated Fluvial Alluvium (comprised of various lithologies like Quartzite, Granite, or Basalt)
Sandstone (clastic)
Clastic Sedimentary Rock (primarily composed of SiO2)
Sandstone (with cross-bedding)
Arenite (composed primarily of Quartz: SiO2)
Siltstone
Siltstone (composed of microscopic silt-sized particles of quartz and feldspar)
Sandstone (Red Sandstone)
Arenite
Limestone
Calcite rock (CaCO3)
Chert (with inclusions)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Ironstone (Limonitic Sandstone)
Ferruginous Sandstone (rich in Limonite: FeO(OH)·nH2O)
Fossilized Crinoid Stem
Class Crinoidea (Echinodermata)
Marble
Recrystallized Calcite / Dolomite (CaCO3)
Limestone
Calcium Carbonate (CaCO3)
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Granite (likely biotite granite)
Coarse-grained granitic rock; chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende
Favosites Fossil (Honeycomb Coral)
Favosites goldfussi / Order Tabulata