Sandstone (likely Arkose or Lithic)
Clastic sedimentary rock (SiO2 + impurities)
Category
Browse sedimentary (base), then artificial specimens identified by the Rock Identifier community.
Sandstone (likely Arkose or Lithic)
Clastic sedimentary rock (SiO2 + impurities)
Jasper (Iron-rich)
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) impurities
Bituminous Coal
Organic Sedimentary Rock (Carbon-based)
Sandstone
Arenite (SiO2 principal)
Chert (specifically Yellow Jasper variety)
Silicon Dioxide (SiO2)
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Iron oxide inclusions
Chert (Chert Nodule)
Microcrystalline quartz (SiO2)
Asphalt Concrete (Bituminous Concrete)
Bituminous aggregate
Chalcedony (Grey/White Agate)
Silicon Dioxide (SiO₂)
Sandstone
Arenite
Agate (specifically, multi-colored or pastel-dyed agate)
Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).
River Stone (Greywacke)
Greywacke (Lithic Sandstone)
Coquina
Bioclastic Limestone
Gravel or Pebble
Clastic Sedimentary Grain (typically composed of Quartz or Silicate minerals)
Sandstone (lithic/greywacke variety)
Arenite (composed primarily of SiO2 with various lithic fragments)
Coquina
Bioclastic Limestone
Fossiliferous Limestone (Shell Fragment)
Biogenic Limestone (Calcium Carbonate / CaCO3)
Chert (and associated Sedimentary rocks)
Microcrystalline Silica (SiO2)
Pyrite Concretion (Grapestone)
Iron Sulfide (FeS2) Concretion
Polygenetic Conglomerate (Puddingstone)
Conglomerate (SiO2 matrix with mixed clasts)
Limestone Gravel
Calcium Carbonate (CaCO3)
Sandstone (Quartzite-rich)
Clastic Sedimentary Rock (primarily SiO2)
Sandstone (likely Quartzose Sandstone)
Arenite (primarily SiO2)
Sandstone (Ferruginous)
Arenite with Iron Oxide cement
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily Quartz with Limonite/Goethite staining)
Coquina or Fossilized Shell Aggregate
Calcareous bioclastic sedimentary rock (CaCO3)
Polygenetic Conglomerate (or Breccia)
Clastic Sedimentary Rock
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Puddingstone (specifically Gowganda Tillite or St. Joseph Island Puddingstone)
Jasper Conglomerate
Fossil Shark Tooth
Carcharodon sp. (likely Otodus or similar Lamniformes order)
Fossilized Shark Tooth (Dermal Denticle or worn tooth fragment)
Elasmobranchii (fossil remains)
Sandstone
Arenite (SiO2 based)
Sandstone
Arenite (primarily SiO2)
Druzy Quartz on Limestone
Silicon Dioxide (SiO2)
Agate
Agate (a variety of Chalcedony, SiO2)
Sandstone (lithic wake/graywacke variety)
Arenite/Greywacke (SiO2 with lithic fragments)
Mixed Tumbled Gemstones (Agate, Aventurine, Pyrite, etc.)
Multiple (principally Silicon Dioxide SiO2 and Iron Disulfide FeS2)
Sandstone
Arenite (SiO2 based)
Sandstone
Arenite (SiO2 based)
Sandstone
Arenite (SiO2 based)
Limestone Cobble
Sedimentary Calcium Carbonate (CaCO3)
Limestone
Sedimentary Calcium Carbonate (CaCO3)