Fossilized tooth, likely mammalian molar
Silicified or mineral-replaced mammalian tooth; exact taxon cannot be determined from the image
fossil
Category
Mineral (Silicate Replaced Organic Material)
Browse mineral (silicate replaced organic material) specimens identified by the Rock Identifier community.
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Chert (containing Fossil Inclusions)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper nodule)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
metamorphic
Unidentified gray rock fragment
Indeterminate from image; possibly quartz- or feldspar-rich silicate material
mineral
Flint (chert), likely brown flint
Microcrystalline quartz/chalcedony (SiO₂)
sedimentary
Elephant Skin Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Beryl (Emerald variety in host rock)
Be3Al2(SiO3)6 (Silicate mineral)
mineral
Petrified Wood
Silicified Wood / Xylopal
fossil
Fossilized Coral
Cnidaria fossil / Calcite-replaced coral
fossil
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide / Chalcedony)
metamorphic
Petrified Wood
Silicified wood (Quartz replacement of organic wood structure)
fossil
Chert / Flint
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Cryptocrystalline Quartz (SiO2)
sedimentary
Raw Amber / Resin Mineral
Succinite (Fossilized Tree Resin)
gemstone
Fossilized Bark
Lepidodendron / Sigillaria fossil impression
fossil
Likely weathered igneous rock fragments
Indeterminate; possibly basaltic or granitic rock with quartz, feldspar, and dark mafic minerals
igneous
Petrified Wood
Silicified Wood (primarily SiO₂ - Silicon Dioxide)
metamorphic
Coral Fossil (Hexagonaria)
Hexagonaria sp. (Silica-replaced)
fossil
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Fossilized Shark Tooth (Megalodon or Carcharocles species fragment)
Otodus megalodon / Carcharocles spp. (Apatite / Calcium Phosphate)
fossil
Fossilized Bone Fragment
Vertebrate Fossil Material (Apatite/Calcium Phosphate)
fossil
Jasper
Silicon Dioxide (Microcrystalline Quartz / Chalcedony)
sedimentary
Chert (Yellow Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Limonite (Ironstone)
Limonite (mixture of hydrated iron oxides, primarily Goethite α-FeO(OH))
mineral
Fossil oyster shell
Fossilized bivalve, commonly Ostrea or Crassostrea
fossil
Fossil Shell (Bivalve)
Class Bivalvia (fossilized)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Polished brecciated jasper
Silicified microcrystalline quartz (chalcedony), commonly called jasper
sedimentary
Moss Agate
Chalcedony (SiO2) with inclusions of hornblende or chlorite
mineral
Petrified Wood (Silicified Wood)
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
mineral
Druzy Chalcedony/Quartz on Fluorite core
Silicon Dioxide (SiO2) on Calcium Fluoride (CaF2)
mineral
Chert (often called Flint or Agate nodule)
Cryptocrystalline Quartz (SiO2)
sedimentary
Fossilized Bivalve Shell (Fossilized Clam)
Bivalvia (class) / CaCO3 (Calcium Carbonate)
fossil
Chert Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
sedimentary
Yellow Beryl (Heliodor)
Beryllium aluminum silicate (Be3Al2Si6O18)
mineral
Chert / Jasper
Microcrystalline Quartz (SiO2)
sedimentary