Limestone (specifically Dolomitic/Crystalline Limestone)
Sedimentary Carbonate Rock (CaCO3 / CaMg(CO3)2)
sedimentary
Category
Fossil
Browse fossil specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO₂)
sedimentary
Fossilized Sea Urchin Spines
Echinoidea (Cidaroid spines)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
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)
Chert (White Chert/Flint)
Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)
sedimentary
Chalk / Sedimentary Limestone
Calcium Carbonate (CaCO3) - Biogenic Sedimentary Rock
sedimentary
Dolomite or Limestone (Carbonate Rock)
CaMg(CO3)2 (Dolomite) or CaCO3 (Limestone / Calcite)
sedimentary
Sulfidic Mudstone with Pyrite/Goethite
Sulfidic Siltstone/Mudstone (FeS2)
sedimentary
Slate
Slate (Foliated metamorphic rock)
metamorphic
Chalk
Calcium Carbonate (CaCO3)
sedimentary
Ammolite
Biogenic gemstone (Aragonite, CaCO3)
mineral
Sandstone (lithic wacke/arenite)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Glacial Cobbles (predominantly Granite and Gneiss)
Mixed lithologies (Quartz, Feldspar, Mica assemblage)
igneous and metamorphic
Sandstone
Arenite (Secondary classification based on grain size)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Slate
Slate (Metamorphic Rock)
metamorphic
Sandstone with Liesegang Rings
Clastic sedimentary rock (Sandstone with iron oxide rhythmic precipitation)
sedimentary
Crushed Limestone
Calcium Carbonate (CaCO3)
Sedimentary
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Petoskey Stone
Hexagonaria percarinata (Fossilized Coral)
sedimentary
Shale
Shale
sedimentary
Amber
Succinite (a Fossilized Tree Resin); Chemical formula is approximately C10H16O
Organic mineraloid
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2 permineralization)
sedimentary
Sandstone
Sandstone (lithified quartz arenite, arkose, graywacke, etc. depending on composition)
Sedimentary Rock
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Chert (within Asphalt)
Chert (SiO2)
sedimentary
Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)
Sedimentary Rock
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
Riverstone (Sandstone Pebble)
Arenite (SiO2 with various lithic fragments)
sedimentary
Red Sandstone
Arenite (primarily Quartz and Feldspar with Iron Oxide 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)