Rock Identifier

Category

Organic (Geological Interest)

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

Caliche (also known as hardpan, calcrete, kankar) (Primarily composed of calcium carbonate (CaCO₃), often mixed with other minerals like quartz, clay minerals, and iron oxides.) — Mineral

Caliche (also known as hardpan, calcrete, kankar)

Primarily composed of calcium carbonate (CaCO₃), often mixed with other minerals like quartz, clay minerals, and iron oxides.

Petrified Wood (Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)) — Mineral/Fossil (Sedimentary context)

Petrified Wood

Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)

Mineral/Fossil (Sedimentary context)

Fancy Jasper (Agate/Chert mix) (Silicon Dioxide (SiO2) with impurities) — sedimentary

Fancy Jasper (Agate/Chert mix)

Silicon Dioxide (SiO2) with impurities

Septarian Nodule (Septarian Concretion (CaCO3 with Siderite/Calcite/Aragonite)) — sedimentary

Septarian Nodule

Septarian Concretion (CaCO3 with Siderite/Calcite/Aragonite)

Puddingstone (Conglomerate (specifically a type of jasper conglomerate or quartz conglomerate)) — Sedimentary

Puddingstone

Conglomerate (specifically a type of jasper conglomerate or quartz conglomerate)

Red Jasper (Silicon dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions) — sedimentary

Red Jasper

Silicon dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Chert (often called Flint when found in chalk/limestone) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint when found in chalk/limestone)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Amber (Succinite (Carbon-based organic compound; approximate formula C10H16O)) — Mineraloid

Amber

Succinite (Carbon-based organic compound; approximate formula C10H16O)

Fossiliferous Limestone (Calcite-rich Sedimentary Rock (CaCO3)) — sedimentary

Fossiliferous Limestone

Calcite-rich Sedimentary Rock (CaCO3)

Ironstone Concretion (Iron-rich Mudstone) (Siderite / Geothite concretion (FeCO3 / FeO(OH))) — sedimentary

Ironstone Concretion (Iron-rich Mudstone)

Siderite / Geothite concretion (FeCO3 / FeO(OH))

Ironstone Concretion (Siderite or Hematite Concretion) — sedimentary

Ironstone Concretion

Siderite or Hematite Concretion

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Amber (Succinite (specific to Baltic amber), fossilized tree resin) — mineraloid

Amber

Succinite (specific to Baltic amber), fossilized tree resin

Travertine (Calcareous Tufa (CaCO3)) — sedimentary

Travertine

Calcareous Tufa (CaCO3)

Travertine (often colloquially called Tufa) (Chemical Sedimentary Calcium Carbonate (CaCO3)) — sedimentary

Travertine (often colloquially called Tufa)

Chemical Sedimentary Calcium Carbonate (CaCO3)

Petrified Wood (Silicified wood (Quartz/Chalcedony - SiO2)) — sedimentary

Petrified Wood

Silicified wood (Quartz/Chalcedony - SiO2)

Travertine (Tufa) (Calcium Carbonate (CaCO3)) — sedimentary

Travertine (Tufa)

Calcium Carbonate (CaCO3)

Petrified Wood (Silicified Wood (primarily SiO2 - Silicon Dioxide / Chalcedony)) — metamorphic

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide / Chalcedony)

Septarian Nodule (Dragon Stone) (Septarian Nodule (Calcium Carbonate/Aragonite/Calcite Concretion)) — sedimentary

Septarian Nodule (Dragon Stone)

Septarian Nodule (Calcium Carbonate/Aragonite/Calcite Concretion)

Red Sandstone (Arenite (Iron-rich Sandstone)) — sedimentary

Red Sandstone

Arenite (Iron-rich Sandstone)

Banded Chert (Microcrystalline silicon dioxide (SiO2)) — sedimentary

Banded Chert

Microcrystalline silicon dioxide (SiO2)

Weathered iron-rich limestone or sandstone (Ferruginous carbonate/siliciclastic rock; likely calcite- and iron-oxide-bearing matrix) — sedimentary

Weathered iron-rich limestone or sandstone

Ferruginous carbonate/siliciclastic rock; likely calcite- and iron-oxide-bearing matrix

Greywacke (likely) (Greywacke (a type of sandstone)) — Sedimentary

Greywacke (likely)

Greywacke (a type of sandstone)

Jasper (Agate/Jasper (Microcrystalline Quartz, SiO2)) — sedimentary

Jasper

Agate/Jasper (Microcrystalline Quartz, SiO2)

Water and Silt (Sedimentary Environment) (Suspended Sediment / H2O (dihydrogen monoxide)) — sedimentary

Water and Silt (Sedimentary Environment)

Suspended Sediment / H2O (dihydrogen monoxide)

Petrified Wood (Silicified Wood (SiO2)) — mineral

Petrified Wood

Silicified Wood (SiO2)

Fossilized Gastropod (Snail) (Class Gastropoda (internal mold or 'steinkern')) — sedimentary

Fossilized Gastropod (Snail)

Class Gastropoda (internal mold or 'steinkern')

Jasper (Silicon Dioxide (Microcrystalline Quartz / Chalcedony)) — sedimentary

Jasper

Silicon Dioxide (Microcrystalline Quartz / Chalcedony)

Sandstone Pebble (River Rock) (Sandstone (Quartz-rich sedimentary rock with iron oxide staining)) — sedimentary

Sandstone Pebble (River Rock)

Sandstone (Quartz-rich sedimentary rock with iron oxide staining)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Black Marble with Quartz Veining (Metamorphosed Limestone (Recrystallized CaCO3)) — metamorphic

Black Marble with Quartz Veining

Metamorphosed Limestone (Recrystallized CaCO3)

Sandstone (with carbonaceous plant fragments) (Arenite (composed primarily of SiO2)) — sedimentary

Sandstone (with carbonaceous plant fragments)

Arenite (composed primarily of SiO2)

Green Moss Agate (Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite) — sedimentary

Green Moss Agate

Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite

Red Sandstone with Reduction Spot (Quartzose Sandstone with a Leach/Reduction Spot) — sedimentary

Red Sandstone with Reduction Spot

Quartzose Sandstone with a Leach/Reduction Spot

Chert with Calcite Veining (Microcrystalline Quartz (SiO2) with Calcium Carbonate (CaCO3) veins) — sedimentary

Chert with Calcite Veining

Microcrystalline Quartz (SiO2) with Calcium Carbonate (CaCO3) veins

Moss Agate (Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides) — Mineral (Variety of Chalcedony)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides

Mineral (Variety of Chalcedony)

Pyrite (Iron Pyrite (FeS2)) — mineral

Pyrite

Iron Pyrite (FeS2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Ambergris (Marine Coprolite/Subfossil) (Marine organic coprolite / Ambergris (Physeter macrocephalus metabolite)) — fossil

Ambergris (Marine Coprolite/Subfossil)

Marine organic coprolite / Ambergris (Physeter macrocephalus metabolite)

Basaltic Tuff / Volcanic Breccia (Pyroclastic Breccia / Lithic Tuff) — igneous

Basaltic Tuff / Volcanic Breccia

Pyroclastic Breccia / Lithic Tuff

Black Chert (Flint) (Microcrystalline Quartz (SiO2)) — sedimentary

Black Chert (Flint)

Microcrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)