Chert (or Flint)
Chert (cryptocrystalline quartz), SiO2
Sedimentary
Category
Limestone
Browse limestone specimens identified by the Rock Identifier community.
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone with Crinoid Stem
Bioclastic Limestone (CaCO3)
sedimentary
Chert (with Quartz veins)
Microcrystalline Quartz (SiO2)
sedimentary
Brachiopod Fossil in Limestone
Phylum Brachiopoda, Class Rhynchonellata
sedimentary
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fossil Coral (Petoskey Stone or Favosites)
Favosites (specifically Hexagonaria percarinata if silica-replaced Michigan type)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Flint variety)
Chert (SiO2)
sedimentary
Chert with Limestone matrix
Microcrystalline silica (SiO2) in Calcite (CaCO3) matrix
sedimentary
Chert (variations include Chalcedony and Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Lapis Lazuli
Lapis lazuli (primary mineral: Lazurite, (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)
metamorphic
Fossilized Coral (Honeycomb Coral)
Favosites (extinct genus of tabulate corals), CaCO3 (Calcium Carbonate)
sedimentary
Crinoid Marble
Crinoidal Limestone/Marble
fossil
Chert Nodule in Limestone
Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)
sedimentary
Fossil Bivalve Shell
Class Bivalvia (e.g., Veneriidae family)
sedimentary
Fossilized Gastropod in Limestone
Gastropoda (Class) in Fossiliferous Limestone
sedimentary
Lapis Lazuli
Lapis lazuli (complex rock; primarily Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)
metamorphic
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Fossiliferous Limestone with Coral Imprint
Fossiliferous Limestone (CaCO3)
sedimentary
Travertine
Terrestrial Sedimentary Limestone (CaCO3)
sedimentary
Bivalve Fossil (Clam)
Class Bivalvia, likely Mercenaria or similar genus
fossil
Fossiliferous Limestone with Rugose Coral
Rugosa (order), typically preserved in CaCO3 (Calcite)
sedimentary
Fossiliferous Limestone (Coral Fossil)
Scleractinian Coral in Calcium Carbonate (CaCO3)
sedimentary
Fossiliferous Limestone with Brachiopod
Limestone (Calcium Carbonate, CaCO3) with Phylum Brachiopoda fossil
sedimentary
Druzy Quartz on Limestone
Silicon Dioxide (SiO2)
mineral
Fossilized Gastropod in Limestone
Gastropoda (Class) in Calcium Carbonate (CaCO3)
sedimentary
Microcrystalline Limestone
Limestone (CaCO3 with impurities)
sedimentary
Chert (within Limestone)
Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)
sedimentary
Quartz on Limestone
Silicon Dioxide (SiO2) on Calcium Carbonate (CaCO3)
Mineral on Sedimentary
Marble
Recrystallized Calcite / Metamorphosed Limestone (CaCO3)
metamorphic
Fossiliferous Limestone (Chert/Clay mixed)
Calcium Carbonate (CaCO3) / Silicon Dioxide (SiO2)
sedimentary
Fossiliferous Limestone (Chertified Limestone)
Calcium Carbonate (CaCO3) often replaced by Microcrystalline Silica (SiO2)
sedimentary
Travertine (Tufa)
Chemical Limestone (CaCO3)
sedimentary
Marble
Metamorphosed Limestone (CaCO3)
metamorphic
Coquina
Coquina Limestone (CaCO3)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (CaCO3)
sedimentary
Coquina
Biogenic Limestone (Coquina)
sedimentary
Marble
Metamorphic Limestone (CaCO3)
metamorphic
Coquina
Biogenic Limestone (CaCO3)
sedimentary
Marble
Metamorphosed Limestone (CaCO3)
metamorphic
Coquina
Coquina (Bioclastic Limestone)
sedimentary