Chert (Concretion or Nodular Variety)
Microcrystalline Quartz (SiO2)
sedimentary
Category
Mineral (Silicate Replaced Organic Material)
Browse mineral (silicate replaced organic material) specimens identified by the Rock Identifier community.
Learn about Mineral (Silicate Replaced Organic Material) in the encyclopedia
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Petrified Wood
Silicified Wood (primarily SiO2)
fossil
Chert (specifically Green Chert/Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Iron-stained fossiliferous rock, possibly fossil wood
Likely silicified/petrified wood in iron-rich silica matrix; exact identification requires microscopy
fossil
Chert / Flint
Silicon Dioxide (SiO2)
sedimentary
Moss Agate
Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide
mineral
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Jasper (Green Jasper / Chert)
Silicon Dioxide (SiO2 with inclusions)
mineral
Fossilized tooth, likely a mammalian tooth fragment
Indeterminate fossil tooth; possibly an ungulate or carnivoran tooth
fossil
Chert (Fossiliferous)
Silicon dioxide (SiO2)
sedimentary
Chert Concretion
Microcrystalline Quartz (SiO2)
sedimentary
Megalodon Shark Tooth
Otodus megalodon
fossil
Fossil Shark Tooth (Sand Tiger or Mackerel Shark)
Carcharias sp. or Otodus sp. replaced by Hydroxylapatite/Calcium Carbonate
sedimentary
Fossil Brachiopod
Phylum Brachiopoda
fossil
Petrified Wood
Silicified wood (principally SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Chert (Flint)
Chert (Microcrystalline or cryptocrystalline Quartz - SiO2)
sedimentary
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Yellow Chert
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (Nodule)
Microcrystalline Quartz (SiO2)
sedimentary
Fossil Coral (Favosites Honeycomb)
Favosites (Genus), Phylum Cnidaria, Class Anthozoa
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
mineral
Fossil ammonite
Ammonite (subclass Ammonoidea; exact species not identifiable from the image)
fossil
Green Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Chert (Gravel pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Tumbled brown jasper (likely common jasper or chert)
Microcrystalline quartz, SiO₂, chiefly chalcedony/quartz with iron-oxide impurities
mineral
Fossiliferous Rock (likely Dinosaur Fossil in Matrix)
Permineralized Vertebrate Fossil (Calcium Carbonate/Silica replaced bone material)
sedimentary
Unidentified polished mineral specimen
Indeterminate; likely a pale feldspar or quartz-bearing material
mineral
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Polished/tumbled brecciated jasper (likely rainforest or ocean jasper)
Microcrystalline quartz (SiO₂), commonly mixed with chalcedony, iron oxides, and other silicates
mineral
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Lepidodendron Fossil (Scale Tree)
Lepidodendron
fossil
Polished orbicular jasper
Orbicular jasper; microcrystalline quartz (SiO₂) with hematite/goethite and other silicate inclusions
sedimentary
Fossilized Horn Coral
Rugosa (Tetracoralla)
fossil
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (often called Flint)
Chert (Cryptocrystalline Silica, SiO2)
sedimentary
Jasper (brecciated or orbicular jasper)
Microcrystalline quartz (SiO₂), commonly mixed with hematite, goethite, chlorite, and other silicates
sedimentary
Chert
Cryptocrystalline Quartz (SiO2)
sedimentary