Chert (Chert Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Category
Fossil
Browse fossil specimens identified by the Rock Identifier community.
Sandstone (Quartzose)
Arenite (predominantly SiO2)
sedimentary
Sandstone or Limestone
Arenite or Calcareous Sedimentary Rock
Sedimentary
Chert (Green variety)
Chert (Silicon Dioxide, SiO2)
sedimentary
Sandstone
Arenite
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Limestone (specifically Dolomitic/Crystalline Limestone)
Sedimentary Carbonate Rock (CaCO3 / CaMg(CO3)2)
sedimentary
Shale creek bed
Shale (fine-grained clastic sedimentary rock)
Sedimentary
Shale
Shale (fine-grained clastic sedimentary rock)
Sedimentary
Shale or Argillite
Shale (sedimentary) / Argillite (metamorphic)
Sedimentary or Metamorphic (low-grade)
Slate
Slate (Foliated metamorphic rock)
metamorphic
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Slate
Slate (Metamorphic Rock)
metamorphic
Chalk / Sedimentary Limestone
Calcium Carbonate (CaCO3) - Biogenic Sedimentary Rock
sedimentary
Chert (White Chert/Flint)
Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)
sedimentary
Dolomite or Limestone (Carbonate Rock)
CaMg(CO3)2 (Dolomite) or CaCO3 (Limestone / Calcite)
sedimentary
Sandstone (lithic wacke/arenite)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Ammolite
Biogenic gemstone (Aragonite, CaCO3)
mineral
Chalk
Calcium Carbonate (CaCO3)
sedimentary
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Crushed Limestone
Calcium Carbonate (CaCO3)
Sedimentary
Petoskey Stone
Hexagonaria percarinata (Fossilized Coral)
sedimentary
Petrified Wood
Silicified Wood (SiO2 permineralization)
sedimentary
Amber
Succinite (a Fossilized Tree Resin); Chemical formula is approximately C10H16O
Organic mineraloid
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Sandstone
Sandstone (lithified quartz arenite, arkose, graywacke, etc. depending on composition)
Sedimentary Rock
Shale
Shale
sedimentary
Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)
Sedimentary Rock
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Chert (within Asphalt)
Chert (SiO2)
sedimentary
Chert (Flint)
Chert (microcrystalline quartz)
sedimentary
Sandstone
Arenite (a specific type of sandstone with less than 15% matrix)
Sedimentary rock
Sandstone or Mudstone with Iron Staining
Ferruginous Sandstone/Mudstone
Sedimentary
Red Sandstone
Arenite (primarily Quartz and Feldspar with Iron Oxide cement)
sedimentary
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Sedimentary Rock
Sandstone (Ferruginous)
Clastic Sedimentary Rock (SiO2 with Fe2O3/FeOOH cement)
sedimentary
Concretion or Geode (unbroken)
Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.
Sedimentary rock (specifically a concretion or possibly a geode)
Petrified Wood
Silicified wood (Quartz/Chalcedony)
Sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Sandstone (Pebble/Cobble)
Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)
Sedimentary
Ammolite
Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)
mineral