Concretion
Septarian Concretion
Category
Browse mineral or sedimentary (if chert) specimens identified by the Rock Identifier community.
Concretion
Septarian Concretion
Ferruginous Sandstone (Gozzanous)
SiO2 (Quartz) with FeO(OH) (Goethite) or Fe2O3 (Hematite) coating
Calcite (Yellow/Orange variety - sometimes called Honey Calcite)
Calcite
Sandstone (with potentially metamorphic or basaltic bands)
Arenite / Lithic Wacke
Turquoise
Turquoise (Hydrated phosphate of copper and aluminium), CuAl6(PO4)4(OH)8·4H2O
Fossilized Megalodon Tooth Fragment
Otodus megalodon (Carcharocles megalodon fossil)
Quartz (Milky/Crystalline variety)
Silicon Dioxide (SiO2)
Pyrite
Iron Sulfide (FeS2)
Banded Calcite (often sold as 'Mexican Onyx' or 'Calcite Onyx')
Calcite (Calcium Carbonate, CaCO3)
Sandstone
Arenite (SiO2 principal)
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite or Limonite inclusions
Banded Jasper (Carnelian Jasper)
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Desert Varnish on Sandstone
Ferromanganese coating on Quartz Arenite
Yellow Jasper
Silicon dioxide (SiO2)
Concretion (Sandstone)
Carbonate-cemented Sandstone Concretion
Jasper (Tumbled)
Silicon Dioxide (SiO₂)
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
Concrete with Aggregate
Artificial Conglomerate (Cement and Aggregate)
Quartz / Common Gravel
Silicon Dioxide (SiO2)
Garnet in Matrix (Schist or Quartz)
Almandine Garnet, Fe3Al2(SiO4)3
Almandine Garnet in Matrix
Almandine, Fe3Al2(SiO4)3
Carnelian (Chalcedony)
Silicon Dioxide (SiO2)
Banded Gneiss
Gneiss (High-grade regional metamorphic rock)
Shale with Iron Staining
Fissile Argillaceous Sedimentary Rock
Granite Gneiss
Gneiss (High-grade metamorphic rock)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Bauxite
Bauxite (Mixture including Gibbsite Al(OH)3, Boehmite γ-AlO(OH), and Diaspore α-AlO(OH))
Bauxite
Bauxite (Mixture of Al(OH)3, AlO(OH), and Fe2O3)
Glauconitic Sandstone (Greensand)
Glauconitic Quartz Arenite (containing Glauconite, (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)
Shale or Mudstone River Pebble
Argillaceous sedimentary rock
Kyanite in Quartz
Kyanite (Al2SiO5) with Quartz (SiO2)
Quartz (Small Fragment)
Silicon Dioxide (SiO2)
Bauxite
Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))
Quartz Geode
Silicon Dioxide (SiO2)
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Sandstone (likely Ferruginous)
Sandstone (SiO2 with iron oxides)
Limonite (Iron Ore)
Hydrous ferric oxides (FeO(OH)·nH2O)
Unidentifiable Specimen
Undetermined
Mica Schist
Mica Schist
Red Jasper
Silicon dioxide (SiO2) with hematite impurities
Sandstone Concretion
Clastic sedimentary rock (primarily Quartz SiO2)