Limestone
Calcium Carbonate (CaCO3)
sedimentary
Category
Organic Specimen (Fossil)
Browse organic specimen (fossil) specimens identified by the Rock Identifier community.
Limestone (Porous/Travertine variant)
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Fossiliferous Chert (Chert with Crinoid Stem Impression)
Chert (SiO2) with fossil Anthozoan or Crinoid columnals
sedimentary
Amber
Succinite (C10H16O)
mineraloid
Pyrite
Iron Sulfide (FeS2)
mineral
Petrified Wood
Silicified Wood (primarily SiO₂ - Silicon Dioxide)
metamorphic
Amber
Succinite
Organic Mineral
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Dendritic Agate
Chalcedony (SiO2) with manganese/iron oxide inclusions
mineral
Limonitic Sandstone with Inclusion
Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)
sedimentary
Chert (Siliceous Mudstone variant)
Microcrystalline quartz (SiO2)
sedimentary
Amber
Succinite (fossilized resin); C10H16O
mineraloid
Fossiliferous Limestone (Coquina / Shell Limestone)
Bioclastic Limestone (CaCO3)
sedimentary
Sandstone (Iron-stained)
Clastic sedimentary rock (SiO2 with Fe2O3 staining)
sedimentary
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Amber
Succinite (C10H16O)
mineral
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Fossiliferous Limestone (Crinoidal Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Fossil Coral (Favosites)
Favosites (Order: Tabulata, Phylum: Cnidaria)
sedimentary
Calcite on Limestone (or Fossil)
Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Amber
Succinite (specifically for Baltic amber); chemical formula approx. C10H16O
Organic Gemstone (fossilized resin)
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
sedimentary
Sandstone (Ferruginous)
Arenite with Iron Oxide cement
sedimentary
Sandstone with Bedding Planes
Arenite (Sedimentary rock composed primarily of sand-sized minerals)
sedimentary
Fossilized Shark Tooth (Basal Bone)
Otodus sp. (Mineralized Hydroxyapatite)
sedimentary
Chert (containing Fossil Inclusions)
Microcrystalline Quartz (SiO2)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Amber
Succinite (Fossilized Resin)
mineral
Iridescent Ammonite
Ammonoidea (Species: likely Cleoniceras or Desmoceras); Mineral: Aragonite/Ammolite (CaCO3)
sedimentary (fossilized)
Fossiliferous Chert (with Brachiopod or Mollusk fragments)
Silicon dioxide (SiO2) with Calcium Carbonate (CaCO3) inclusions
sedimentary
Petrified Wood
Silicified Wood (SiO2 permineralization)
sedimentary
Geode (unopened)
Chert / Chalcedony Geode (SiO2)
sedimentary
Brachiopod Fossil in Limestone
Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)
sedimentary
Weathered Sandstone with Algae Growth
Arenite
sedimentary
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
mineral
Fossil Shell (Bivalve)
Phylum Mollusca, Class Bivalvia (typically composed of Calcium Carbonate / CaCO3)
sedimentary
Chert (specifically a flint nodule component)
Microcrystalline quartz (SiO2)
sedimentary
Sandy Ironstone
Ferruginous Sandstone
sedimentary
Petrified Wood
Silicified Wood (SiO2)
Mineral / Fossil