Petrified Wood
Silicified Wood (SiO2)
fossil
Category
Biogenic Material
Browse biogenic material specimens identified by the Rock Identifier community.
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Basaltic Tuff / Volcanic Breccia
Pyroclastic Breccia / Lithic Tuff
igneous
Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (Clastic Sedimentary Rock)
sedimentary
Sandstone
Arenite (primarily Quartz, SiO2)
sedimentary
Botryoidal chalcedony (likely white quartz/chalcedony)
Microcrystalline quartz, SiO₂; possibly partly altered carbonate or opaline silica
mineral
Green Glass Cullet / Recycled Glass
Amorphous Silicon Dioxide (SiO2) with various metal oxides
Man-made Glass (Not a natural rock or mineral)
Vesicular volcanic rock, likely weathered scoria
Scoria (vesicular basaltic-andesitic volcanic rock), composition approximately plagioclase, pyroxene, and volcanic glass
igneous
Red Sandstone
Arenite (SiO2 with Fe2O3)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Chert (or Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Quartzite
Quartzite (primarily SiO2)
metamorphic
Limestone
Limestone (Calcium Carbonate, CaCO3)
Sedimentary
Carnelian/chalcedony rough
Microcrystalline quartz (SiO₂), iron-oxide-colored chalcedony
mineral
Fossilized Bone Fragment
Petrified Osseous Material
fossil
Slag (Industrial Glass/Glassy Rock)
Anthropogenic Vitreous Material
igneous
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Tumbled yellow quartz (likely citrine or iron-stained quartz)
Quartz, SiO₂; yellow color from trace iron or irradiation/heat-related coloration
mineral
Banded gneiss pebble
Biotite–quartz–feldspar gneiss (composition variable)
metamorphic
Petrified wood
Silicified wood, chiefly microcrystalline quartz (SiO₂)
fossil
Tumbled jasper or rhyolitic porphyry
Silicic volcanic rock, likely rhyolite (quartz- and feldspar-rich), possibly jasperized
igneous
Serpentine
Serpentine group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4)
metamorphic
Mudstone
Argillite / Siliciclastic sedimentary rock
sedimentary
Quartz / Quartzite
Silicon Dioxide (SiO2)
Mineral / Metamorphic
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone (Tumbled/River Pebble)
Arenite (composed primarily of SiO2)
sedimentary
Limestone
Calcite (CaCO3)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite with Iron Oxide matrix
sedimentary
Petrified Wood
Petrified Wood (Silicified Wood)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Jasper
Silicon Dioxide (SiO2)
mineral
Chert Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Mudstone
Lutylite (group of fine-grained sedimentary rocks)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of cellulose)
fossil
Polished tiger’s-eye cabochon (probable)
Quartz variety, SiO₂, with fibrous riebeckite/crocidolite-derived inclusions
metamorphic
Quartzite
Quartz-rich metamorphic rock; chiefly SiO₂
metamorphic
Biotite schist (likely graphite-bearing)
Mica schist; chiefly quartz + biotite mica, with possible graphite and feldspar
metamorphic
Limestone
Sedimentary rock composed mainly of calcium carbonate (CaCO3)
sedimentary
Coquina / Limonite-stained Limestone
Sedimentary Limestone with Iron Oxyhydroxide (FeO(OH)·nH2O)
sedimentary