Hag Stone
Perforated sedimentary rock (typically limestone, sandstone, or flint)
sedimentary
Category
Mineralized Fossil
Browse mineralized fossil specimens identified by the Rock Identifier community.
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Petrified Wood
Silicified Wood (SiO2)
sedimentary
Agatized Fossil (Druzy Agate)
Silicon Dioxide (SiO2) replacing organic matter
sedimentary
Fossilized Coral (Petoskey Stone type)
Hexagonaria percarinata (Order: Rugosa)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Sandstone
Arenite (SiO2 based)
sedimentary
Shale
Fissile Mudstone (Shale)
sedimentary
Sandstone (Ferruginous)
Arenite (Fe2O3 staining)
sedimentary
Petoskey Stone (Fossilized Rugose Coral)
Hexagonaria percarinata
fossil
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Sandstone Pebble
Arenite (Clastic Sedimentary Rock)
sedimentary
Coprolite
Coprolite (fossilized feces)
sedimentary
Ferruginous Sandstone (Ironstone Nodules)
Ferruginous Sandstone with Limonite/Goethite coating (Fe2O3·H2O)
sedimentary
Shale
Shale (Lutite)
sedimentary
Shiva Eye Shell Fossil (Operculum)
Turbo marmoratus (Operculum)
fossil
Fossiliferous Limestone
Carbonate sedimentary rock (CaCO3)
sedimentary
Sandstone
Arenite (SiO2, often with CaCO3 or Fe2O3 cement)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Megalodon Tooth
Otodus megalodon
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
fossil
Fossil Coral (Petoskey Stone / Favosites / Charlevoix Stone)
Hexagonaria percarinata / Favosites (Cnidaria)
fossil
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Sandstone
Arenite (SiO2 based with quartz, feldspar, or lithic fragments)
sedimentary
Sandstone
Arenite (SiO2 principal component)
sedimentary
Sandstone (with vugs)
Arenite / Sedimentary Sandstone
sedimentary
Weathered Sandstone with Algae Growth
Arenite
sedimentary
Polished ammonite fossil
Ammonoidea (likely a Jurassic or Cretaceous ammonite), preserved in limestone/mudstone
fossil
Fossil Shark Tooth
Elasmobranchii (Lamniformes order likely)
fossil
Stromatolite
Biogenic sedimentary structure (Stromatolite)
fossil
Sandstone
Arenite
sedimentary
Fossilized Coral (Petoskey Stone type)
Hexagonaria percarinata (Fossilized Rugose Coral)
fossil
Petrified Wood
Silicified Wood (primarily SiO2)
fossil
Fossilized Coral (Petoskey Stone precursor)
Hexagonaria percarinata (Fossilized Rugose Coral)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Fossiliferous limestone, likely coral or shell fragment
Calcitic limestone (primarily CaCO₃), containing preserved marine bioclasts
fossil
Fossilized Shark Tooth
Elasmobranchii dentition (calcium phosphate / hydroxyapatite)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Sandstone
Arenite (primarily SiO2)
sedimentary
Petrified Wood (Black / Carbonized)
Silicon Dioxide (Quartz/Chalcedony replacing Organic Matter)
fossil
Yellow Chalcedony (Tumbled/Cabochon)
Silicon dioxide (SiO2)
mineral
Amber
Succinite (C10H16O)
mineral