Fossilized Shark Tooth
Carcharhinus sp. (likely Bull or Requiem shark family)
sedimentary
Category
Mineral Like Biological Tissue
Browse mineral like biological tissue specimens identified by the Rock Identifier community.
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Chert
Silicon dioxide (SiO2)
sedimentary
Petrified wood
Silicified wood, commonly quartz/chalcedony (SiO₂) replacing wood tissue
fossil
Fossilized Shark Tooth
Carcharocles sp. or Striatolamia sp. (Phosphate/Carbonate mineralized Hydroxyapatite)
sedimentary
Lemon (Mock specimen mimicking Citrine/Sulfur)
Citrus x limon
Organic (Biological specimen)
Polished fossil tooth or jaw fragment
Indeterminate vertebrate dental/bone fossil; likely mineralized enamel and dentine
fossil
Kidney Stone (Urolith / Calcium Oxalate Stone)
Calcium Oxalate Monohydrate (Whewellite) / Calcium Oxalate Dihydrate (Weddellite)
mineral
Sandstone with Foliose Lichen
Arenite (Rock matrix) with Xanthoparmelia or Flavoparmelia (Lichen genus)
sedimentary
Petrified Wood (Black / Carbonized)
Silicon Dioxide (Quartz/Chalcedony replacing Organic Matter)
fossil
Optical Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Amber
Succinite (fossilized tree resin)
Organic Mineraloid
Pearl (Biogenic Mineraloid)
Calcium carbonate (CaCO3) primarily as Aragonite
mineral
Pearl
Calcium Carbonate (CaCO3)
mineral
Fossilized tooth fragment, likely mammalian
Mineralized dentine and enamel; exact taxon indeterminate from the photograph
fossil
Fossil shell or shell fragment
Likely a calcareous bivalve or gastropod fragment; precise identification requires locality and microscopy
fossil
Pearl
Calcium Carbonate (Aragonite and Calcite), CaCO3
mineral
Pearl (incorporated into jewelry)
Aragonite and Calcite (CaCO3)
mineral
Fossil Shark Tooth
Carcharocles or Lamniformes (order)
fossil
Kidney Stone
Nephrolith (typically Calcium Oxalate - CaC2O4)
mineral
Petrified Wood
Silicified Wood (SiO2)
mineral
Fossil coral fragment
Likely calcitic colonial coral, possibly fossilized scleractinian coral
fossil
Amber
Succinite (specifically for Baltic amber); chemical formula approx. C10H16O
Organic Gemstone (fossilized resin)
Polished petrified wood
Silicified wood; commonly quartz/chalcedony (SiO₂) replacing cellular tissue
fossil
Fossil bone or tooth fragment
Mineralized fossil vertebrate bone/tooth; exact taxon cannot be determined from the photograph
fossil
Bivalve Fossil (Brachiopod or Scallop)
Class Bivalvia (or potentially Phylum Brachiopoda)
fossil
Spider Conch Shell
Lambis lambis (Calcium Carbonate, CaCO3)
sedimentary
Dendritic Limestone
Calcite with Manganese Oxide (Manganese Dendrites)
sedimentary
Petrified wood
Silicified fossil wood, commonly quartz/chalcedony (SiO₂) replacing wood
fossil
Pearl (Cultured Freshwater)
Calcium Carbonate (Aragonite) - CaCO3
mineral
Pearl
Aragonite / Calcium Carbonate (CaCO3)
mineral
Pearl
Calcium Carbonate (CaCO3) - mainly Aragonite and Calcite
mineral
Pearl
Organic gemstone (Calcium carbonate / CaCO3 + Conchiolin)
mineral
Tufa
Calcareous Tufa (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2 permineralization)
fossil
Pyrite-bearing Rock
Iron Sulfide (FeS2)
mineral
Petrified Wood
Silicified wood (Quartz replacement)
fossil
Pearl
Organic Mineraloid (CaCO3 + Conchiolin)
mineral
Pearl
Nacre (Aragonite and Conchiolin), CaCO3
mineral
Sandstone with Lichen and Iron Oxide Staining
Quartz Arenite / Sandstone
sedimentary
Chert
Silicon dioxide (SiO2)
sedimentary
Chert or Flint
Silicon dioxide (SiO2)
sedimentary
Fossilized wood (petrified wood), likely silicified
Petrified wood; predominantly microcrystalline quartz (SiO₂) replacing wood tissue
fossil