Possible fossilized shell or coral fragment
Indeterminate biogenic carbonate, likely calcite (CaCO₃)
fossil
Category
Organic Materia (Not A Rock Or Mineral)
Browse organic materia (not a rock or mineral) specimens identified by the Rock Identifier community.
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Pyrite in Slate or Shale
Iron Sulfide (FeS2) in Argillaceous Matrix
mineral
Coquina / Shelly Sandstone
Calcareous Sandstone / Coquina
sedimentary
Agate (Moss or Dendritic Agate)
Chalcedony (Silicon Dioxide, SiO2)
mineral
Bivalve Fossil in Sedimentary Matrix
Fossiliferous Mudstone (Class: Bivalvia)
sedimentary
Polished agate-like stone (uncertain; possibly a fossil or shell fragment)
Likely microcrystalline quartz (chalcedony), SiO₂; exact identification is limited by the image
mineral
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions
mineral
Coprolite
Fossilized Feces
fossil
Chalcedony in Matrix (likely Agatized Coral or Chert)
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Sea Shell (Mollusk Shell)
Calcium Carbonate (Aragonite/Calcite)
fossil
Chert with Quartz Vein
Silicon dioxide (SiO2)
sedimentary
Polished plume agate
Chalcedony (microcrystalline SiO₂) with iron-oxide inclusions
mineral
Jasper
Silicon dioxide (SiO2)
sedimentary
Gray River Pebble (likely Limestone or Siltstone)
Sedimentary Rock (Calcium Carbonate or Siliciclastic)
sedimentary
Fossilized Shark Tooth
Chondrichthyes (Class)
fossil
Orbicular granite (likely Rapakivi-type granite)
Granite, chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende
igneous
Siltstone with Fossil Cast
Sedimentary Rock (Siltstone / Fine-grained Sandstone)
sedimentary
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Fossil-bearing Sedimentary Rock
Sedimentum cum fossili
fossil
Pyrite on Limestone
Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix
sedimentary (matrix) / mineral (inclusion)
Bituminous Coal (with Anthracite or Vitrinite inclusion)
Organic-rich Sedimentary Rock (Carboniferous classification)
sedimentary
Black Shale
Argillaceous Chert/Shale
sedimentary
Agate (Moss or Green Agate)
Silicon Dioxide (SiO2)
mineral
Sandstone Concretion
Sedimentary Clastic Rock (Silicate-rich)
sedimentary
Tumbled banded agate (likely chalcedony)
Microcrystalline quartz, SiO₂; probable banded chalcedony/agate
mineral
Petrified Wood
Silicified wood / Permineralized wood (SiO2)
fossil
Pyrite in Shale
Iron Sulfide (FeS2) in Sedimentary Matrix
mineral
Basaltic Tuff / Volcanic Breccia
Pyroclastic Breccia / Lithic Tuff
igneous
Limestone Concretion (Botryoidal/Calcareous Nodules)
Calcium Carbonate Concretion (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Limestone with Calcite Veining
Sedimentary Rock (Calcium Carbonate, CaCO3)
sedimentary
Ferruginous Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
mineral
Pearl strand
Nacreous pearl, primarily aragonite (CaCO₃) with conchiolin protein
gemstone
Petrified Wood
Silicified Wood (SiO2)
fossil
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified wood (primarily Quartz, SiO2)
fossil
River Cobble (Sandstone)
Arenite (primarily SiO2)
sedimentary
Glauconitic Sandstone (Greensand)
Glauconitic Quartz Arenite (containing Glauconite, (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)
sedimentary
Chert (Jasper-rich)
Silicon Dioxide (SiO2)
sedimentary
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Chert / Chalcedony
Silicon Dioxide (SiO2)
sedimentary