Fossil Coral
Cnidaria Anthozoa (Fossilized)
Category
Browse sedimentary rock (technically a variety of chalcedony) specimens identified by the Rock Identifier community.
Fossil Coral
Cnidaria Anthozoa (Fossilized)
Sardonyx Cameo
Silicon Dioxide (SiO2) - variety Cryptocrystalline Quartz
Shale (possibly)
Shale (fine-grained clastic sedimentary rock)
Sandstone (Quartzose Sandstone)
Clastic sedimentary rock (SiO2 major component)
Limestone (specifically Chalky Limestone)
Calcium Carbonate (CaCO3 / Calcite)
Sandstone (Quartzose Sandstone)
Arenite (primarily SiO2)
Sandstone Cobble
Arenite (Secondary classification based on grain size)
Shale
Shale (comprised mostly of clay minerals and quartz)
Limestone
Calcium Carbonate (CaCO3)
Blue Quartzite
Quartzite (primarily SiO2 with inclusions)
Sandstone (Picture Sandstone)
Arenite (primarily SiO2)
Serpentine (Greenstone)
Antigorite, Lizardite, and Chrysolite mixture (Mg3Si2O5(OH)4)
Banded Agate (Pink Chalcedony)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Quartzite
Quartzite (primarily SiO2)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 cementation)
Shale
Fissile mudstone (primarily clay minerals and silt-sized quartz)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Chert / Flint (River Pebble)
Cryptocrystalline Quartz (SiO2)
Granite
Granite
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2)
Magnetite (Lodestone variety)
Magnetite (Fe3O4)
Sandstone (Quartz-rich)
Arenite (composed mainly of SiO2)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2)
Desert Rose
Gypsum (variety Selenite) or Barite, CaSO4·2H2O
Cockle Shell (Fossil or Recent)
Class Bivalvia, Family Cardiidae (e.g., Cerastoderma edule for common cockle)
Sandstone (likely Graywacke or Arkose variant)
Clastic Sedimentary Rock (Lithic Sandstone)
Bronzite
MgSiO3 (Enstatite with 10-30% FeSiO3 in solid solution)
Chert (Field Stone)
Chert (SiO2)
Sandstone
Arenite
Basalt
Basalt (Mafic volcanic rock)
Basalt with Porphyritic Texture
Porphyritic Basalt
Basalt (with possible iron oxide staining)
Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
Picture Jasper
Silicon Dioxide (SiO2) - Opaque Impure Chalcedony
Petrified Wood
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, SiO2)
Banded Chert
Microcrystalline Quartz (SiO2)
Shale creek bed
Shale (fine-grained clastic sedimentary rock)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Sandstone (Beach Pebble)
Clastic sedimentary rock (primarily Quartz and Feldspar)