Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Category
Mineral Like Biological Tissue
Browse mineral like biological tissue specimens identified by the Rock Identifier community.
Learn about Mineral Like Biological Tissue in the encyclopedia
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Pearl (nacre)
Calcium Carbonate (mostly CaCO3 as Aragonite) and Conchiolin
Organic Mineraloid
Fossilized Shark Tooth (likely Sand Tiger Shark)
Carcharias taurus (fossilized hydroxyapatite/calcium phosphate)
fossil
Petrified Wood
Silicified Wood (primarily SiO2)
fossil
Polished fossilized wood (likely petrified wood)
Silicified wood; primarily quartz (SiO₂) replacing wood tissue
fossil
Fossil fish slab
Fossilized fish remains, likely a laminated shale-hosted vertebrate fossil; exact taxon is indeterminate from the image
fossil
Tumbled pale brown stone, possibly petrified wood or chalcedony
Indeterminate from image; likely microcrystalline quartz (SiO₂) or silicified wood
mineral
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Undetermined Due to Blur (Possible Flesh-Tone Mineral)
Unknown (Insufficient Visual Clarity)
Mineral
Freshwater Pearl
Calcium Carbonate (CaCO3) in the form of Aragonite and Calcite
gemstone
Sandstone with Lichen
Arenite (SiO2 based) with biological weathering
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Chalcedony (Agate/Seashell replacement)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Fossiliferous Rock (likely Dinosaur Fossil in Matrix)
Permineralized Vertebrate Fossil (Calcium Carbonate/Silica replaced bone material)
sedimentary
Limonite (Yellow Ochre)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
mineral
Calcite (Yellow/Orange variety - sometimes called Honey Calcite)
Calcite
Mineral
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Manganese Oxide Crust on Limestone
Manganese Oxides (e.g., Pyrolusite MnO2 or Romanechite) on CaCO3
sedimentary
Belemnite Fossil
Belemnitida (Order within Cephalopoda)
sedimentary
Petrified Wood
Silicified Wood (Permineralized organic tissue)
fossil
Chert
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Pearl
Calcium carbonate (CaCO3) as Aragonite or Calcite
mineral
Baroque Pearl
Biogenic Calcium Carbonate (Aragonite/Conchiolin)
mineral
Possible fossil tooth or bone fragment
Indeterminate fossilized vertebrate material; species cannot be identified reliably from this image
fossil
Echinoid Fossil (Fossilized Sea Urchin)
Echinoidea
fossil
Orthoceras Fossil
Orthoceras regulare (Extinct Cephalopod)
fossil
Iron-stained fossiliferous rock, possibly fossil wood
Likely silicified/petrified wood in iron-rich silica matrix; exact identification requires microscopy
fossil
Calcite
Calcium Carbonate (CaCO3)
mineral
Natural Pearl (appearing in a jewelry setting)
Calcium Carbonate (mostly Aragonite), CaCO3 with Conchiolin
mineral
Pearl
Biogenic CaCO3 (Aragonite)
mineral
Polished moss agate pendant
Moss agate, a chalcedony variety of microcrystalline quartz (SiO₂), with green chlorite/actinolite inclusions
mineral
Petrified Wood
Silicified Wood (Per mineral content: SiO2, Quartz/Chalcedony)
fossil
Seashell Fragment (Aragonite/Calcite)
Calcium Carbonate (CaCO3) - Shell fragment
sedimentary
Tree agate (dendritic agate)
Microcrystalline quartz (SiO₂) with manganese- or iron-oxide dendrites
mineral
Weathered Sandstone with Algae Growth
Arenite
sedimentary
Shark Tooth Fossil
Carcharodonta (order Lamniformes), likely Carcharias spp.
fossil
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Black Freshwater Pearls
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
mineral
Fossilized wood (petrified wood)
Silicified fossil wood; commonly quartz/chalcedony (SiO₂) replacing wood
fossil
Fossil coral (likely solitary rugose coral)
Rugosa; possibly genus Heliophyllum or similar
fossil
Dinosaur Bone (Gembone)
Agatized Dinosaur Bone (Silicified Paleo-osteoid)
metamorphic