Chert
Microcrystalline Silicon Dioxide (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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Pink Rhodonite
Manganese Silicate (MnSiO3)
mineral
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (likely brown flint)
Microcrystalline quartz, SiO₂ (chalcedonic quartz aggregate)
sedimentary
Tumbled pale brown stone, possibly petrified wood or chalcedony
Indeterminate from image; likely microcrystalline quartz (SiO₂) or silicified wood
mineral
Chert (Yellow/Brown variety)
Chert (SiO2)
sedimentary
Fossilized Horn Coral
Order Rugosa (Rugose Coral)
sedimentary
Charoite
Charoite (Complex silicate mineral rock)
metamorphic
Iron-rich quartz specimen (likely hematite/goethite-coated quartz)
Quartz (SiO₂) with iron oxides, chiefly hematite (Fe₂O₃) and/or goethite (FeO(OH)); precise identification requires testing
mineral
Chert (and Flint)
Silicon Dioxide (SiO2)
sedimentary
Petrified Bone (Fossil Bone)
Per mineralization fossil bone (varies by organism, predominantly replacement by SiO2 - Quartz/Chalcedony)
fossil
Polished fossil gastropod shell
Fossilized gastropod (snail) shell; exact taxon cannot be determined from the image
fossil
Fossilized Shark Tooth
Carcharodon carcharias (fossilized) / Hydroxyapatite permineralized with silica or iron
sedimentary
Dendritic jasper/chalcedony
Silica-rich microcrystalline quartz (SiO₂) with manganese-oxide dendrites
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (primarily Chalcedony or Quartz, SiO2)
sedimentary
Petrified Wood (Calamites Fossil)
Calamites sp. (Silicified/Permineralized Plant Fossil)
sedimentary
Unidentified greenish-gray rock fragment
Tentatively altered basalt or basaltic volcanic rock; mineral identification requires testing
igneous
Tumbled jasper, likely ocean or brecciated jasper
Microcrystalline quartz (SiO₂) with iron-oxide and other mineral impurities
mineral
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Red Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of organic matter)
fossil
Likely bituminous coal
Coal, predominantly carbon-rich organic matter with variable maceral and mineral content
sedimentary
Green Jasper (with Quartz veining)
Jasper (Silica-rich microcrystalline variety of Quartz), formula: SiO2
sedimentary
Tumbled brown jasper
Microcrystalline quartz/chalcedony (SiO₂), commonly iron-oxide stained
sedimentary
Slag (Industrial Byproduct)
Anthropogenic Vitreous Silicate material
igneous
Petrified Wood
Silicified wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
metamorphic
Grey Limestone
Calcium Carbonate (CaCO3)
sedimentary
Fossilized Shark Tooth (Root Portion)
Selachimorpha (partial specimen)
fossil
Polished fossiliferous limestone pebble
Fossiliferous micritic limestone, probably containing gastropod or bivalve fragments
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Black Onyx and Mother of Pearl
Cryptocrystalline Quartz (SiO2) and Nacre (Calcium Carbonate)
mineral
Zircon
Zirconium Silicate (ZrSiO₄)
mineral
Chert (variations include Flint or Jasper)
Silicon Dioxide (SiO2)
sedimentary
Tourmalinated Quartz
Silicon dioxide (SiO2) with inclusions of Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)3OH)
mineral
Plume Agate
Silicon Dioxide (SiO2) - Chalcedony Variety
mineral
Druzy quartz-bearing rock
Quartz, SiO₂, as a druse coating or quartz-rich vein material
mineral
Rough White Zircon
Zircon (Zirconium Silicate, ZrSiO4)
mineral
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of cellulose)
fossil
Kaolinite (Chalky Clay)
Kaolinite (Al2Si2O5(OH)4)
sedimentary