Chalcedony (Common Opal variant)
Silicon dioxide (SiO2) with varying levels of hydration
mineral
Category
Fossil
Browse fossil specimens identified by the Rock Identifier community.
Shale
Clastic sedimentary rock (primarily clay and silt minerals)
sedimentary
Fossilized Shark Tooth (Fragment)
Elasmobranchii fossil (likely Cretalamna or Squalicorax genus)
sedimentary
Red Sandstone
Clastic sedimentary rock (primarily SiO2 with Fe2O3)
sedimentary
Chert (Nodular or Fossiliferous)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert (and Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (Iron-stained)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite
sedimentary
Gastropod Steinkern (Fossil Snail Internal Mold)
Class Gastropoda (Internal Mold)
sedimentary
Fossiliferous Limestone (Coquina / Shell Limestone)
Bioclastic Limestone (CaCO3)
sedimentary
Fossilized Coral (Petoskey Stone type)
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Dinosaur Fossil (Skull)
Dinosauria fossilis (Petrified Hydroxyapatite / Calcium Carbonate)
sedimentary
Coral Fossil (Favosites)
Favosites (Calcite/Calcium Carbonate, CaCO3)
sedimentary
Flexicalymene Trilobite Fossil
Flexicalymene meeki (Order Phacopida, Family Calymenidae)
sedimentary
Brachiopod Fossil in Chert
Phylum Brachiopoda within Microcrystalline Quartz (SiO2)
sedimentary
Crinoid Stem Fossil
Class Crinoidea (Phylum Echinodermata), primarily Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Chert (Siliceous Mudstone variant)
Microcrystalline quartz (SiO2)
sedimentary
Sandstone
Arenite (SiO2 based with various cements)
sedimentary
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Amber
Succinite (fossilized resin)
mineral
Red Sandstone
Arenite (primarily Quartz, SiO2, with Iron Oxide cementing agent)
sedimentary
Amber
Succinite (Approximate formula: C10H16O)
mineral
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 predominantly)
sedimentary
Limestone (Fossiliferous)
Calcium Carbonate (CaCO3) - Bioclastic Limestone
sedimentary
Amber
Succinite (Approximate formula: C10H16O)
Mineraloid
Coquina / Shelly Limestone
Bioclastic Limestone (composed of CaCO3)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony/Opal replacing organic matter)
sedimentary
Fossilized Coral (Petoskey Stone or Rugose Coral)
Antophyllum (Hexagonaria) or Scleractinia (CaCO3)
sedimentary
Petrified Wood
Silicified wood (Quartz, Chalcedony, or Opal)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Pyrite in Shale
Iron Disulfide (FeS2) in Argillaceous Shale
sedimentary
Crinoid Stem Fragment
Crinoid (Phylum Echinodermata, Class Crinoidea)
sedimentary
Fighting Conch (Sea Shell)
Strombus alatus (primarily composed of Calcium Carbonate / CaCO3)
mineral
Sandstone (Weathered)
Arenite (primarily SiO2)
sedimentary
Red Sandstone
Arenite (with Iron Oxide cement)
sedimentary
Sandstone
Arenite (primarily composed of SiO2)
sedimentary
Chert (specifically Gray/Blue Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fossil / Permineralized Bone
Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)
sedimentary
Brachiopod Fossil (Spiriferid)
Phylum Brachiopoda, Order Spiriferida (CaCO3 - Calcium Carbonate)
sedimentary (fossilized organic remains)
Coral Fossil (Petrified Coral)
Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)
sedimentary