Likely petrified wood
Silicified wood, chiefly microcrystalline quartz (SiO₂)
fossil
Category
Mineral Like Biological Tissue
Browse mineral like biological tissue specimens identified by the Rock Identifier community.
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Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Fossilized tooth, likely mammalian molar
Silicified or mineral-replaced mammalian tooth; exact taxon cannot be determined from the image
fossil
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Fossil shark tooth
Likely fossilized shark tooth, possibly Carcharhinus or Otodus species
fossil
Pearl (with Peridot)
Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4
mineral
Fossilized tooth or tooth fragment
Indeterminate vertebrate tooth; likely mammalian, mineralized hydroxyapatite
fossil
Amber
Succinate (Organic Fossilized Resin)
mineraloid
Chert (Jasper/Carnelian variety)
Microcrystalline Quartz (SiO2)
sedimentary
Fossiliferous limestone (likely stromatoporoid/coral limestone)
Calcite-rich carbonate rock, chiefly CaCO₃; visible fossil structures may be tabulate coral or stromatoporoid
fossil
Bivalve Fossil (Internal Mold)
Class Bivalvia (Phylum Mollusca)
sedimentary
Chert (variant Flint/Novaculite)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Limestone with Algal/Lichen Colonization
Calcium Carbonate (CaCO3)
sedimentary
Snowflake Obsidian
Volcanic glass containing Spherulite inclusions (primarily Cristobalite, SiO2)
igneous
Petrified wood
Silicified fossil wood, commonly quartz/chalcedony (SiO₂) replacing woody tissue
fossil
Fossil-bearing Sedimentary Rock
Sedimentum cum fossili
fossil
Otodus Shark Tooth
Otodus obliquus
fossil
Natural or Cultured Pearl
Calcium Carbonate (Aragonite and Conchiolin), CaCO3
Mineral (Organic)
Chert with Quartz Vein
Microcrystalline Quartz (SiO2)
sedimentary
Amber
Succinates (C10H16O)
mineraloid
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
sedimentary
Brachiopod Fossil in Chert
Phylum Brachiopoda within Microcrystalline Quartz (SiO2)
sedimentary
Fossilized Shark Teeth in Matrix
Cretaceous Chondrichthyes (Shark) remains in Sedimentary Matrix
fossil
Chert (also known as Flint or Common Chalcedony)
Cryptocrystalline Silica (SiO2)
sedimentary
Fossilized Brachiopod Shell
Order Spiriferida (likely)
fossil
Fossilized tooth fragment, possibly a mammalian tooth
Indeterminate fossil tooth; enamel and dentine, taxon not identifiable from this fragment
fossil
Knightia Fossil in Limestone
Knightia eocaena in micritic limestone
sedimentary
Weathered fossil shell fragment
Indeterminate bioclastic carbonate, likely molluscan shell (calcium carbonate, commonly aragonite or calcite)
fossil
Chert / Flint
Microcrystalline Silica (SiO2)
sedimentary
Tufa
Calcareous Tufa (CaCO3)
sedimentary
Belemnite (Fossilized Rostrum)
Belemnitida (Order), composed of Calcite (CaCO3)
sedimentary
Petrified Bone (Fossil Bone)
Per mineralization fossil bone (varies by organism, predominantly replacement by SiO2 - Quartz/Chalcedony)
fossil
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
White aragonite (coralloid/botryoidal aragonite)
Aragonite, CaCO₃; orthorhombic polymorph of calcite
mineral
Blue apatite (likely rough/tumbled specimen)
Apatite group, commonly fluorapatite — Ca5(PO4)3F
mineral
Brachiopod Fossil in Sedimentary Matrix
Phylum Brachiopoda in Siltstone/Mudstone matrix
fossil
Chert / Flint
Cryptocrystalline Quartz (SiO2)
sedimentary
Amber
Succinate (Fossilized Resin)
mineral
Chert (Chert breccia)
SiO2 (Silicon Dioxide)
sedimentary