Sandstone (with carbonaceous plant fragments)
Arenite (composed primarily of SiO2)
sedimentary
Category
Organic Materia (Not A Rock Or Mineral)
Browse organic materia (not a rock or mineral) specimens identified by the Rock Identifier community.
Learn about Organic Materia (Not A Rock Or Mineral) in the encyclopedia
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Petrified Wood
Silicified wood (primarily quartz, SiO2)
fossil
Chert (Polished/Tumbled)
Silicon Dioxide (SiO2)
sedimentary
Amber (Copal)
Fossilized Tree Resin
mineraloid
Chert (Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Tumbled agate (likely moss or plume agate)
Microcrystalline quartz, primarily chalcedony (SiO₂), with iron-oxide and other mineral inclusions
mineral
Chert / Flint
Silicon Dioxide (SiO2)
sedimentary
Sandstone Concretion
Arenaceous concretion (primarily SiO2 with Fe2O3 staining)
sedimentary
Red Sandstone
Arenite (Iron-rich Sandstone)
sedimentary
Coal (most likely Bituminous or Anthracite)
Coal (organic sedimentary rock)
Sedimentary
Shungite
Fullerene-bearing carbonaceous rock
mineral
Anthropogenic Heat Source (Electronic/Industrial Interface)
Thermal IR emission (Electronic infrastructure)
not a rock or mineral
River Rock
Silica-rich water-worn rock
sedimentary
Chert with Quartz Veining
Microcrystalline silica (SiO2)
sedimentary
Dendritic Agate (Tree Agate)
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
mineral
Fossil plant impression slab
Fossilized plant compression/impression; exact taxon indeterminate from the image
fossil
Sandstone with Vitrinite/Coal inclusions
Arenite with Carbonaceous inclusions
sedimentary
Sandstone
Arenite
sedimentary
Chert (concretionary/nodular variant)
Microcrystalline Quartz (SiO2) with possible fossil or mineral inclusions
sedimentary
Shale
Fissile mudstone (primarily clay minerals and silt-sized quartz)
sedimentary
Fossil Coral
Scleractinia (Fossilized Coral) / Calcium Carbonate (CaCO3) or Silica (SiO2)
fossil
Fossiliferous Shale
Carbonaceous Shale (with potential plant/aquatic fossils)
sedimentary
Bivalve seashell
Calcareous shell, primarily aragonite (CaCO₃); likely a modern cockle or related bivalve
fossil
Green Moss Agate
Silicon Dioxide (SiO2) with Mineral Inclusions
sedimentary
Bivalve Fossil (Clam Stone)
Phylum Mollusca, Class Bivalvia
fossil
Tree Agate (or Moss Agate)
Dendritic Agate (Silicon Dioxide - SiO2)
mineral
Dendritic Agate (Tree Agate)
Chalcedony (Silicon Dioxide, SiO2) with Manganese or Iron Oxide inclusions
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Jasper (specifically Polychrome or Desert Jasper)
Silicon Dioxide (SiO2) with iron oxide and other mineral impurities
sedimentary (chemical/biological origin)
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)
sedimentary
Iron-rich chert or jasper
Microcrystalline quartz (SiO₂), commonly colored by hematite/goethite
sedimentary
Chert / Jasper
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Mosasaur Tooth Fossil
Mosasaurus sp.
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Shale
Shale (Sedimentary rock composed of mud/clay minerals)
sedimentary
Shale
Mudrock / Fissile Shale
sedimentary
Likely pyrite-bearing rock fragment
Pyrite, FeS₂, possibly in a dark host rock
mineral
Ironstone Concretion (Limonite/Goethite)
Goethite/Limonite concretion (FeO(OH)·nH2O)
sedimentary
Limestone (Tufa/Travertine)
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Graphite-bearing schist (probable)
Graphite schist; chiefly quartz, mica, and graphite
metamorphic