Rock Identifier

Category

Organic (Geological Interest)

Browse organic (geological interest) specimens identified by the Rock Identifier community.

Chert (Arrowhead variety) (Chert (SiO2)) — sedimentary

Chert (Arrowhead variety)

Chert (SiO2)

Fossilized tooth, likely a mammalian tooth fragment (Indeterminate fossil tooth; possibly an ungulate or carnivoran tooth) — fossil

Fossilized tooth, likely a mammalian tooth fragment

Indeterminate fossil tooth; possibly an ungulate or carnivoran tooth

Moss Agate (Silicon Dioxide with inclusions (SiO2)) — mineral

Moss Agate

Silicon Dioxide with inclusions (SiO2)

Petrified Wood (Silicified Wood (primarily SiO2 - Silicon Dioxide)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Petrified Wood (Silicified Wood (SiO2 permineralization)) — fossil

Petrified Wood

Silicified Wood (SiO2 permineralization)

Fossilized Echinoid (Sea Urchin) (Echinoidea (Class) - Often found as Micraster or Clypeaster specimens) — sedimentary

Fossilized Echinoid (Sea Urchin)

Echinoidea (Class) - Often found as Micraster or Clypeaster specimens

Chert Fossil (Pebble) (Microcrystalline Quartz (SiO2) with biogenic inclusions) — sedimentary

Chert Fossil (Pebble)

Microcrystalline Quartz (SiO2) with biogenic inclusions

Liesegang Ring Siltstone (Siltstone with iron oxide Liesegang bands) — sedimentary

Liesegang Ring Siltstone

Siltstone with iron oxide Liesegang bands

Polished amber-like agate or jasper carving (Likely chalcedony (microcrystalline SiO₂), possibly iron-stained carnelian/jasper; exact identification requires testing) — gemstone

Polished amber-like agate or jasper carving

Likely chalcedony (microcrystalline SiO₂), possibly iron-stained carnelian/jasper; exact identification requires testing

Mixed Quartz and Jasper Pebbles (Silicon Dioxide (SiO2)) — Mineral

Mixed Quartz and Jasper Pebbles

Silicon Dioxide (SiO2)

Travertine (Tufa) (Chemical Limestone (CaCO3)) — sedimentary

Travertine (Tufa)

Chemical Limestone (CaCO3)

Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

Chert (and Petrified Wood) (Silicon Dioxide (SiO2)) — sedimentary

Chert (and Petrified Wood)

Silicon Dioxide (SiO2)

Honeycomb Coral Fossil (Favosites (extinct genus of tabulate coral)) — fossil

Honeycomb Coral Fossil

Favosites (extinct genus of tabulate coral)

Petoskey Stone (Hexagonaria percarinata (Calcite / CaCO3)) — fossil

Petoskey Stone

Hexagonaria percarinata (Calcite / CaCO3)

Pearl strand (Nacreous pearl, primarily aragonite (CaCO₃) with conchiolin protein) — gemstone

Pearl strand

Nacreous pearl, primarily aragonite (CaCO₃) with conchiolin protein

Petrified Wood (Silicified wood (Quartz/Chalcedony replacement of cellulose)) — fossil

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement of cellulose)

Petrified Wood (Silicified wood (principally SiO2)) — sedimentary

Petrified Wood

Silicified wood (principally SiO2)

Polished fossiliferous limestone (Bioclastic limestone, commonly crinoidal or shell-rich micrite) — sedimentary

Polished fossiliferous limestone

Bioclastic limestone, commonly crinoidal or shell-rich micrite

Chert (Flint) (Chert (Cryptocrystalline variety of Quartz, SiO2)) — sedimentary

Chert (Flint)

Chert (Cryptocrystalline variety of Quartz, SiO2)

Prasiolite and Quartz Crystal Cluster (Quartz (SiO2); Prasiolite is a variety of Quartz) — mineral

Prasiolite and Quartz Crystal Cluster

Quartz (SiO2); Prasiolite is a variety of Quartz

Petrified Wood (Silicified Wood (primarily SiO2)) — fossil

Petrified Wood

Silicified Wood (primarily SiO2)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Moss Agate (Silicon Dioxide (Chalcedony variety)) — mineral

Moss Agate

Silicon Dioxide (Chalcedony variety)

Chert Nodule (Chert (Microcrystalline Silicon Dioxide, SiO2)) — sedimentary

Chert Nodule

Chert (Microcrystalline Silicon Dioxide, SiO2)

Jasper (Silicon Dioxide (SiO2) with iron oxide impurities) — sedimentary

Jasper

Silicon Dioxide (SiO2) with iron oxide impurities

Chert (variations include Flint or Jasper) (Silicon Dioxide (SiO2)) — sedimentary

Chert (variations include Flint or Jasper)

Silicon Dioxide (SiO2)

Fossil Coral (Petoskey / Horn Coral Sliced Button) (Scleractinia / Rugosa (Silurian-Devonian Anthozoa)) — fossil

Fossil Coral (Petoskey / Horn Coral Sliced Button)

Scleractinia / Rugosa (Silurian-Devonian Anthozoa)

Chert (Jasper variation) (Chert (SiO2)) — sedimentary

Chert (Jasper variation)

Chert (SiO2)

Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

Cultured freshwater pearls (Pearl; primarily aragonite (CaCO₃) in nacre with an organic conchiolin matrix) — gemstone

Cultured freshwater pearls

Pearl; primarily aragonite (CaCO₃) in nacre with an organic conchiolin matrix

Cockle Shell (Fossil or Recent) (Class Bivalvia, Family Cardiidae (e.g., Cerastoderma edule for common cockle)) — Sedimentary (Biogenic, a type of fossil)

Cockle Shell (Fossil or Recent)

Class Bivalvia, Family Cardiidae (e.g., Cerastoderma edule for common cockle)

Sedimentary (Biogenic, a type of fossil)

Pyrite (Pyrite (FeS2)) — Mineral

Pyrite

Pyrite (FeS2)

Quartz (in a rock matrix) (Quartz (SiO2)) — mineral

Quartz (in a rock matrix)

Quartz (SiO2)

Calcite-rich limestone or travertine (Calcite, CaCO₃; likely crystalline limestone/travertine with possible aragonite) — sedimentary

Calcite-rich limestone or travertine

Calcite, CaCO₃; likely crystalline limestone/travertine with possible aragonite

Fossiliferous Limestone (Sedimentary rock containing Indeterminate Fossil remains (likely Crinoid stem or Bryozoan fragment)) — fossil

Fossiliferous Limestone

Sedimentary rock containing Indeterminate Fossil remains (likely Crinoid stem or Bryozoan fragment)

Fossiliferous Siltstone (Clastic Sedimentary Rock with Fossil Inclusions) — sedimentary

Fossiliferous Siltstone

Clastic Sedimentary Rock with Fossil Inclusions

Asphalt aggregate (Human-made bituminous asphalt containing crushed silicate rock aggregate) — sedimentary

Asphalt aggregate

Human-made bituminous asphalt containing crushed silicate rock aggregate

Honey calcite (orange calcite) (Calcite, calcium carbonate (CaCO₃)) — mineral

Honey calcite (orange calcite)

Calcite, calcium carbonate (CaCO₃)

Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

Petrified Wood (Silicified Wood (primarily Chalcedony or Quartz, SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily Chalcedony or Quartz, SiO2)