Limestone
Sedimentary Rock (Primarily CaCO3)
Category
Browse sedimentary (fossil) specimens identified by the Rock Identifier community.
Limestone
Sedimentary Rock (Primarily CaCO3)
Limestone
Calcareous sedimentary rock (CaCO3)
Limestone
Sedimentary rock composed mainly of calcite (CaCO3)
Sandstone (likely Fossiliferous)
Arenite / Sedimentum arenaceum
Siltstone
Siltstone (primarily composed of microcrystalline Quartz and Feldspar)
Concretion
Sedimentary Concretion (Ironstone / Calcite Concretion)
Limestone
Calcium Carbonate (CaCO3)
Sandstone Concretion
Ferruginous Sandstone Concretion
Sandstone
Arenite (SiO2 based)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Limonite pseudo-concretion (Ironstone)
Limonite (FeO(OH)·nH2O) / Goethite
Coral Skeleton (Scleractinia)
Aragonite (CaCO3) biomineralisation within Anthozoa
Yellow Chalcedony (Tumbled/Cabochon)
Silicon dioxide (SiO2)
Bivalve Fossil (Internal Mold)
Class Bivalvia (Phylum Mollusca)
Agatized Fossil or Chalcedony Nodule
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Fossil Coral (Rugose Coral)
Rugosa (extinct order); typically composed of Calcite (CaCO3) or replaced by Quartz (SiO2)
Petrified Wood (Silicified Fossil)
Silicified Wood (SiO2)
Favosites Fossil (Honeycomb Coral)
Favosites sp. (Extinct genus of tabulate coral)
Echinoidea (Fossil Sea Urchin)
Echinodermata Echinoidea
Dendritic Agate
Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions
Fossilized Shark Tooth
Elasmobranchii (fossilized matrix/root section)
Orthoceras Fossil
Orthoceras sp. (Extinct genus of nautiloid cephalopod)
Fossilized Favosites (Honeycomb Coral)
Favosites (extinct genus of tabulate coral)
Sandstone (Ferruginous)
Sandstone (primarily SiO2 with iron oxide cement Fe2O3)
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Biogenic Inclusions
Ironstone Concretion / Limonite-stained Siltstone
Ironstone (primarily Limonite FeO(OH)·nH2O and Siltstone)
Chert (often called Flint or Jasper if reddish)
Microcrystalline Quartz (SiO2)
Calcite-rich limestone fragment
Limestone, predominantly calcite (CaCO₃), possibly micritic or fossiliferous
Limestone
Calcium Carbonate (CaCO3)
Limestone with fossiliferous textures
Bioclastic Limestone (CaCO3)
Limestone
Sedimentary rock composed primarily of Calcium Carbonate (CaCO3)
Chert (River Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Shale creek bed
Shale (fine-grained clastic sedimentary rock)
Chert Nodules (with Quartz Inclusions)
Microcrystalline Quartz (SiO2)
Amber
Organic gemstone (Succinite is common if from the Baltic)
Likely petrified wood
Silicified wood, chiefly microcrystalline quartz (SiO₂)
Fossil shell fragment (likely brachiopod or bivalve)
Indeterminate fossilized carbonate shell; likely Brachiopoda or Bivalvia
Coquina or Fossiliferous Limestone
Fossiliferous Limstone (CaCO3)
Sandstone
Arenite (SiO2 primarily)
Sandstone (River Cobble)
Clastic Sedimentary Rock (primarily Quartz with Feldspar)
Sandstone
Arenite (primarily Quartz, SiO2)
Sandstone (with potential trace fossils)
Clastic sedimentary rock (primarily SiO2)