General Rock and Mineral Collection (Center: Angelite / Blue Anhydrite)
Anhydrite (Calcium Sulfate, CaSO4)
Category
Browse sedimentary (artificial) specimens identified by the Rock Identifier community.
General Rock and Mineral Collection (Center: Angelite / Blue Anhydrite)
Anhydrite (Calcium Sulfate, CaSO4)
Weathered sandstone
Quartz-rich sandstone, likely ferruginous subarkose
Shale with Iron Staining
Fissile Mudrock (Sedimentary Rock)
Shale (with Iron Staining)
Argillaceous mudstone / Shale
Sandstone (Ferruginous)
Arenite (Fe-oxide cemented)
Sandstone (River Cobble / Pebble)
Sedimentary Rock (Quartz Sandstone / Arenite)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Iron Oxide cement)
Shale
Fissile Mudstone
Sandstone (Ferruginous)
Clastic Sedimentary Rock (SiO2 with Fe2O3/FeOOH cement)
Weathered shale or mudstone
Clastic mudrock, chiefly clay minerals, quartz, and feldspar
Weathered sandstone or siltstone cobble
Clastic sedimentary rock, probably quartz-rich sandstone; exact identification requires testing
Polished fossil-bearing shale or mudstone
Fossiliferous carbonaceous mudstone/shale; visible fossils may be bivalves or ammonites, but species cannot be confirmed from the image
Banded sandstone pebble
Quartz-rich sandstone, likely iron-oxide- and organic/mineral-stained; exact variety uncertain
Brachiopod Fossil in Limestone
Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)
Weathered sandstone fragment
Quartz-rich sandstone (compositionally uncertain)
Banded gneiss
Foliated gneiss, likely quartz–feldspar–biotite or amphibole gneiss
Jasper
Silicon dioxide (Microcrystalline Quartz, SiO2)
Small pale stone, possibly quartz or limestone
Indeterminate from image; likely quartz (SiO₂) or calcite-rich limestone (CaCO₃)
Fossil gastropod shell
Fossilized gastropod, likely a small marine snail; exact genus cannot be determined from the image
Quartzite Sandstone / Quartz Sandstone
Quartz Sandstone (SiO2 with minor mineral impurities)
Rounded sandstone or quartz-rich sedimentary pebble
Likely quartz arenite/subarkose; exact identification requires testing
Chert / Flint Arrowheads
Cryptocrystalline Quartz (SiO2)
Pyrite
Iron Disulfide (FeS2)
Mixed Tumbled Gemstones (Agate, Aventurine, Pyrite, etc.)
Multiple (principally Silicon Dioxide SiO2 and Iron Disulfide FeS2)
Polished brown river pebble (likely chert or fine-grained sandstone)
Indeterminate; probable microcrystalline quartz (chert) or quartz-rich sandstone
Orange Calcite
Calcium Carbonate (CaCO3)
Pyrite
Iron Sulfide (FeS2)
Celestine (Celestite)
Strontium sulfate (SrSO4)
Halite (Rock Salt)
Halite (Sodium Chloride, NaCl)
Sandstone
Sedimentary rock composed mainly of quartz sand
Fossiliferous Sandstone / Fossil Fragment
Fossiliferous Sedimentary Matrix with Indeterminate Fossil Material
Banded Sedimentary Rock
Sedimentary rock with Liesegang banding
Quartz-veined Sandstone Pebble
Quartzose Sandstone with Quartz Veinlets
Weathered iron-rich sandstone or ferruginous siltstone
Clastic sedimentary rock, likely quartz-rich sandstone cemented by iron oxides (Fe₂O₃/Fe₃O₄)
Banded Sandstone (River Pebble)
Arenite (SiO2 primarily)
Shale with Trace Fossils
Fissile mudrock (Shale)
Shale
Shale (clastic sedimentary rock)
Sandstone
Arenite
Shale
Shale (Lutite)
Shale
Fissile mudstone (rich in clay minerals and quartz)
Shale
Fissile mudrock (composed primarily of clay minerals and quartz)
Fossiliferous Sedimentary Rock
Sedimentary Rock with Invertebrate Fossil Imprint