Coal
Coal (Combustible sedimentary rock)
sedimentary
Category
Sedimentary (Fossilized Organic Matter)
Browse sedimentary (fossilized organic matter) specimens identified by the Rock Identifier community.
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Sandstone
Arenite (SiO2 variety)
sedimentary
Fossil gastropod shell
Fossilized marine gastropod; exact genus/species requires locality and examination
fossil
Belemnoit (Fossil)
Belemnoidea (Order), Rostrum / Guard
sedimentary
Geode or Concretion
Silica-based Concretion / Quartz Geode
sedimentary
Fossilized Wood (Petrified Wood)
Agatized wood (primarily SiO2)
fossil
Anthracite Coal
Anthracite
sedimentary
Ammonite Fossil
Ammonoidea (primarily composed of Calcite, CaCO3)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone
Arenite (SiO2 principal)
sedimentary
Fossilized Bone Chunk (likely Dinosaur or Large Mammal)
Permineralized Fossil Bone
sedimentary
Fossil Assortment and Geological Specimens
Various (including Ammonoidea)
fossil
Gastropod Fossil
Phylum Mollusca, Class Gastropoda (Calcium Carbonate, CaCO3)
sedimentary
Seashell Fragment
Calcium Carbonate (CaCO3) in the form of Aragonite or Calcite
mineral
Banded Chert
Chert (a microcrystalline variety of quartz, SiO2 with minor impurities)
Sedimentary
Fossil Shell
Invertebrate fossil (Mollusca)
fossil
Fossil Coral
Cnidaria fossil (often Calcium Carbonate / CaCO3)
sedimentary
Sea Urchin Fossil
Echinoidea (test/fossil)
fossil
Fossilized Coral
Hexagonaria (Rugose and Tabulate coral fossils)
fossil
Tumbled amber-like inclusion
Likely amber (fossilized tree resin; complex polymer), but identification is uncertain from the image
gemstone
Chert / Flint
Chert (varietal name for microcrystalline quartz). Chemical formula: SiO₂
Mineral
Fossilized Coral (Petoskey Stone / Favosites)
Hexagonaria percarinata / Favosites sp. (Calcite, CaCO3)
fossil
Fossilized Brachiopod
Phylum Brachiopoda (General mineral composition: Calcite/CaCO₃ or Silica/SiO₂)
sedimentary
Fossilized Blastoid
Pentremites (Class Blastoidea)
sedimentary
Fossilized Brachiopod
Articulata (Class) / Brachiopoda (Phylum)
sedimentary
Petoskey Stone
Hexagonaria percarinata
sedimentary
Banded River Rock with Quartz Vein
Siltstone/Greywacke with Quartz (SiO2)
sedimentary
Concretion (Sandstone)
Carbonate-cemented Sandstone Concretion
sedimentary
Fossiliferous Shale (with Vertebrate Bones)
Laminated Mudstone containing Fossilized Bone (Apatite)
sedimentary
Moss Agate
Chalcedony (Silicon Dioxide with inclusions) - SiO2
mineral
Shale or Argillite
Shale (fine-grained clastic sedimentary rock) or Argillite (low-grade metamorphic rock derived from shale)
Sedimentary or Metamorphic (low grade)
Limpets Shell / Fossil Specimen
Patellogastropoda (Class)
fossil
Geode (Unopened)
Silica Concretion / Geode (Formula: SiO2 for quartz internal contents)
sedimentary
Fossilized Brachiopod or Gastropod
Phylum Brachiopoda / Phylum Mollusca
fossil
Sandstone
Arenite
sedimentary
Sandstone Pebble
Arenite (typically SiO2)
sedimentary
Fossil Shark Tooth
Chondrichthyes dentition (Fossilized Tooth)
fossil
Travertine / Tufa
Calcium Carbonate (CaCO3)
sedimentary
Fossilized Brachiopod Shell Fragment
Brachiopoda (Class: Rhynchonellata or Strophomenata)
fossil
Fossilized Brachiopod
Phylum Brachiopoda (Calcium Carbonate/Silica replacement)
sedimentary
Fossilized Brachiopod
Brachiopoda (Class Rhynchonellata or Spiriferida)
sedimentary