Gneiss (River Cobble)
Gneiss
Category
Browse mineral on sedimentary specimens identified by the Rock Identifier community.
Gneiss (River Cobble)
Gneiss
Magnetite
Fe3O4 (Iron(II,III) oxide)
Druzy Quartz on Ironstone
Silicon Dioxide (SiO2) on Limonitic Ironstone
Blue Quartz
Silicon Dioxide (SiO2) with inclusions
Fluorite
Calcium Fluoride (CaF2)
Bivalve Fossil (Shell-bearing Sedimentary Rock)
Class Bivalvia (Phylum Mollusca) within a Calcarenite/Sandstone matrix
Quartz Pebble
Silicon Dioxide (SiO2)
Unidentified light-colored rock or mineral specimen
Indeterminate; possibly weathered calcite-rich material, limestone, or pale quartz-bearing rock
Cleavable Calcite
Calcium Carbonate (CaCO3)
Yellow Calcite
Calcium Carbonate (CaCO3)
Calcite
Calcium Carbonate (CaCO3)
Pyrite
Iron Disulfide (FeS2)
Optical Calcite
Calcium Carbonate (CaCO3)
Geode or Concretion
Silica-filled nodule (likely SiO2)
Quartz Geode
Silicon Dioxide (SiO2) within a geode
Chalcopyrite
Copper Iron Sulfide (CuFeS2)
Quartz
Silicon Dioxide (SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Jasper
Jasper (Silicon Dioxide, SiO2)
Possible fossilized bone fragment
Indeterminate fossil bone; no species can be identified from this image
Magnetite Ore
Magnetite (Fe3O4)
Quartz Geode
Silicon dioxide (SiO2)
Pyrite
Iron Sulfide (FeS2)
Quartz Geode
Silicon Dioxide (SiO2)
Common Pebble / Sedimentary Rock Fragment
Lithified clastic sediment
Dark mineral nodule with white veining
Possibly a calcite-veined manganese- or iron-rich concretion; exact identification requires testing
Weathered iron-rich sandstone or siltstone
Clastic siliciclastic sedimentary rock, likely ferruginous sandstone/siltstone (quartz-rich, Fe-oxide cement)
Limonite / Ironstone
Hydrated Iron Oxide (FeO(OH)·nH2O)
Banded Metamorphic Rock
Gneiss or Schist
Bornite
Bornite (Cu5FeS4)
Shark Tooth Fossil
Carcharocles megalodon or similar extinct shark tooth
Sandstone
Quartz Arenite / Clastic Sedimentary Rock
Sandstone
Sandstone (SiO2 dominated)
Fossil Snail
Gastropoda (fossilized)
Fossil gastropod shell
Gastropoda; species cannot be determined from the image
Iron-rich sandstone or laterite pebble
Ferruginous sandstone; chiefly quartz (SiO₂) cemented by iron oxides such as hematite/goethite
Sandstone
Clastic sedimentary rock (primarily SiO2)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Milky quartz pebble
Quartz (silicon dioxide, SiO₂)
Weathered quartz-rich pebble
Likely quartz aggregate, SiO₂, possibly quartzite or silicified rock