Chert
Microcrystalline silica (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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Fossilized Shark Tooth
Bioapatite (Calcium Hydroxyapatite) replacement
mineral
Petrified Wood
Silicified Wood (primarily Quartz/SiO2)
mineral
Petrified Wood
Siliconized Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Chert (Flint)
Cryptocrystalline Quartz (SiO2)
sedimentary
Iron-stained quartz-rich rock, possibly jasper or chert
Microcrystalline quartz (SiO₂) with iron oxides/hydroxides
mineral
Gastropod Fossil
Class Gastropoda (fossilized)
fossil
Fossil mammalian skull
Fossilized vertebrate bone; exact taxon cannot be determined from the image
fossil
Dinosaur Bone
Agatized Dinosaur Bone
sedimentary/fossil
Likely petrified wood or silicified fossil fragment
Silicified wood; predominantly microcrystalline quartz (SiO₂)
fossil
Petrified wood
Silicified wood, commonly quartz (SiO₂) replacing woody tissue
fossil
Jasper
Silicon dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Microcrystalline quartz (SiO2)
sedimentary
Jasper
Microcrystalline Quartz (Chalcedony), SiO2
sedimentary
Petrified Wood (Agatized/Silicified Wood)
Silicified Wood / Chalcedony (SiO2)
sedimentary
Shark Tooth Fossil
Vertebrate fossilized tooth (various genera such as Carcharodon, Otodus, or Negaprion)
fossil
Snakeskin Agate
Agate (Cryptocrystalline Quartz, SiO2)
mineral
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Mammoth or Mastodon Tooth Fossil
Proboscidea tooth (Mammuthus or Mammut)
fossil
Ammonite Fossil (Small Pyritized or Calcitized Internal Mold)
Ammonoidea
sedimentary
Chert (Jasper/Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Green Jasper
Microcrystalline Quartz (SiO2) with mineral inclusions
sedimentary
Petrified Wood
Silicified wood (Quartz pseudomorph after wood)
fossil
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)
fossil
Fossil-bearing sedimentary rock, possibly fossil wood or bone
Indeterminate silicified/carbonate fossil in sandstone or mudstone
fossil
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
metamorphic
Fancy Jasper
Jasper (Cryptocrystalline Quartz, SiO2)
sedimentary
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Fossilized wood (petrified wood)
Silicified fossil wood; commonly quartz (SiO₂) replacing wood tissues
fossil
Fossilized Shark Tooth
Chondrichthyes (Class)
fossil
Petrified Wood
Silicified Wood (primarily SiO2)
fossil
Fossilized Shark Tooth
Chondrichthyes (Class) fossilized tooth
fossil
Petrified wood
Silicified fossil wood, commonly quartz/chalcedony (SiO₂) replacing woody tissue
fossil