Rock Identifier

Category

Organic (Paper And Cellulose)

Browse organic (paper and cellulose) specimens identified by the Rock Identifier community.

Learn about Organic (Paper And Cellulose) in the encyclopedia

Andesine

Andesite

Andalusite

Andamooka Opal

Andradite Garnet

Andradite Garnet

Andesine-Labradorite

Andesine-Labradorite

Sapropel

Bituminous Shale

Bituminous Shale

Black Shale

Petrified Wood

Amber

Oil Shale

Sandstone (with biological crust) (Arenite (SiO2 based)) — sedimentary

Sandstone (with biological crust)

Arenite (SiO2 based)

Tumbled orbicular granite or granitic gneiss (Granite, chiefly quartz–feldspar–biotite/amphibole; exact variety uncertain from the image) — igneous

Tumbled orbicular granite or granitic gneiss

Granite, chiefly quartz–feldspar–biotite/amphibole; exact variety uncertain from the image

Black polished/tumbled stone, likely basalt or black jasper (Most likely fine-grained basalt (plagioclase and pyroxene); appearance can also match microcrystalline quartz (black jasper)) — igneous

Black polished/tumbled stone, likely basalt or black jasper

Most likely fine-grained basalt (plagioclase and pyroxene); appearance can also match microcrystalline quartz (black jasper)

Fossil Coral (Petoskey Stone / Rugose Coral) (Hexagonaria percarinata (or similar fossilized rugose/tabulate coral)) — fossil

Fossil Coral (Petoskey Stone / Rugose Coral)

Hexagonaria percarinata (or similar fossilized rugose/tabulate coral)

Tiger's Eye (Pseudomorph of Quartz after Crocidolite (SiO2)) — metamorphic

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Petoskey Stone (Hexagonaria percarinata (Fossilized Rugose Coral)) — sedimentary

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Banded Agate (specifically Sardonyx or Carnelian Agate) (Silicon Dioxide (SiO2) - Cryptocrystalline Quartz) — mineral

Banded Agate (specifically Sardonyx or Carnelian Agate)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Sandstone (likely Quartzose) (Sandstone (Principally SiO2)) — sedimentary

Sandstone (likely Quartzose)

Sandstone (Principally SiO2)

Muscovite Mica (in Quartz matrix) (Potassium aluminum silicate hydroxide fluoride (KAl2(AlSi3O10)(F,OH)2)) — mineral

Muscovite Mica (in Quartz matrix)

Potassium aluminum silicate hydroxide fluoride (KAl2(AlSi3O10)(F,OH)2)

Red Sandstone (Arenite (Ferruginous Sandstone)) — sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Sandstone (Ferruginous) (Arenite with Iron Oxide (Limonite/Hematite) coating) — sedimentary

Sandstone (Ferruginous)

Arenite with Iron Oxide (Limonite/Hematite) coating

Glauconite Siltstone (Glauconitic siltstone / K(Fe,Al,Mg)2[(Si,Al)4O10](OH)2) — sedimentary

Glauconite Siltstone

Glauconitic siltstone / K(Fe,Al,Mg)2[(Si,Al)4O10](OH)2

Muscovite Schist (Muscovite (KAl2(AlSi3O10)(OH)2) in Schist) — metamorphic

Muscovite Schist

Muscovite (KAl2(AlSi3O10)(OH)2) in Schist

Diorite (Phaneritic intermediate plutonic rock) — Igneous

Diorite

Phaneritic intermediate plutonic rock

Painted Sandstone Cobble (Clastic Sedimentary Rock (Sandstone base)) — sedimentary

Painted Sandstone Cobble

Clastic Sedimentary Rock (Sandstone base)

Polished brecciated jasper (likely septarian or iron-rich jasper) (Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and possibly calcite or other rock fragments) — sedimentary

Polished brecciated jasper (likely septarian or iron-rich jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and possibly calcite or other rock fragments

Chalk (Calcium Carbonate (CaCO3)) — sedimentary

Chalk

Calcium Carbonate (CaCO3)

Marble (Recrystallized Calcite (CaCO3) / Marble) — metamorphic

Marble

Recrystallized Calcite (CaCO3) / Marble

Banded Agate (Dyed Purple) (Agate (Variety of Chalcedony/Quartz), SiO2) — mineral

Banded Agate (Dyed Purple)

Agate (Variety of Chalcedony/Quartz), SiO2

Banded Sandstone (Zebra Stone) (Arenite with Iron Oxide Banding (Liesegang rings)) — sedimentary

Banded Sandstone (Zebra Stone)

Arenite with Iron Oxide Banding (Liesegang rings)

Polished orbicular stone, likely granite or diorite (Granite–diorite, composed mainly of feldspar, quartz, and dark amphibole/biotite) — igneous

Polished orbicular stone, likely granite or diorite

Granite–diorite, composed mainly of feldspar, quartz, and dark amphibole/biotite

White Marble (Recrystallized Calcite (CaCO3)) — metamorphic

White Marble

Recrystallized Calcite (CaCO3)

Septarian Nodule (Septarian concretion (Complex mixture of Siderite, Calcite, and Aragonite)) — sedimentary

Septarian Nodule

Septarian concretion (Complex mixture of Siderite, Calcite, and Aragonite)

Fossil Coral (Petoskey Stone / Favosites / Charlevoix Stone) (Hexagonaria percarinata / Favosites (Cnidaria)) — fossil

Fossil Coral (Petoskey Stone / Favosites / Charlevoix Stone)

Hexagonaria percarinata / Favosites (Cnidaria)

Banded Iron Formation (BIF) / Jaspilite (Banded Iron Formation (predominantly Hematite, Magnetite, and Quartz/Jasper)) — sedimentary

Banded Iron Formation (BIF) / Jaspilite

Banded Iron Formation (predominantly Hematite, Magnetite, and Quartz/Jasper)

Banded Iron Formation / Chert with Quartz Veining (Banded Iron Formation (BIF) / Cryptocrystalline Quartz (SiO2)) — sedimentary

Banded Iron Formation / Chert with Quartz Veining

Banded Iron Formation (BIF) / Cryptocrystalline Quartz (SiO2)

Yellow Banded Agate (Silicon Dioxide (SiO₂)) — mineral

Yellow Banded Agate

Silicon Dioxide (SiO₂)

Petoskey Stone (Hexagonaria percarinata (Fossilized Rugose Coral)) — fossil

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Quartz-veined Limestone (Sedimentary limestone with hydrothermal quartz/calcite veins (CaCO3 / SiO2)) — sedimentary

Quartz-veined Limestone

Sedimentary limestone with hydrothermal quartz/calcite veins (CaCO3 / SiO2)

Bauxite (Bauxite (Al(OH)3 mixed with Fe2O3 and clay minerals)) — sedimentary

Bauxite

Bauxite (Al(OH)3 mixed with Fe2O3 and clay minerals)

Banded Calcite (often sold as 'Travertine' or 'Mexican Onyx') (Calcium Carbonate (CaCO3)) — sedimentary

Banded Calcite (often sold as 'Travertine' or 'Mexican Onyx')

Calcium Carbonate (CaCO3)

Dark river pebble, likely basalt or fine-grained volcanic rock (Basalt (probable); mostly plagioclase and pyroxene, with possible magnetite) — igneous

Dark river pebble, likely basalt or fine-grained volcanic rock

Basalt (probable); mostly plagioclase and pyroxene, with possible magnetite

Banded Sandstone (River Cobble) (Arenite Sandstone with heavy mineral layering) — sedimentary

Banded Sandstone (River Cobble)

Arenite Sandstone with heavy mineral layering

Muscovite Mica (Muscovite - KAl2(AlSi3O10)(F,OH)2) — mineral

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(F,OH)2

Pumice (Vesicular Rhyolite/Andesite) (Pumice (a highly vesicular volcanic glass/extrusive igneous rock)) — igneous

Pumice (Vesicular Rhyolite/Andesite)

Pumice (a highly vesicular volcanic glass/extrusive igneous rock)

Clear Quartz (Facet Cut / Polished) (Silicon Dioxide (SiO2)) — mineral

Clear Quartz (Facet Cut / Polished)

Silicon Dioxide (SiO2)

Calcite (Calcium Carbonate (CaCO3)) — mineral

Calcite

Calcium Carbonate (CaCO3)

Sandstone (with Iron Staining) (Quartz Arenite / Ferruginous Sandstone) — sedimentary

Sandstone (with Iron Staining)

Quartz Arenite / Ferruginous Sandstone

Biotite Mica (Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)) — mineral

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)

Polished brown stone, likely smoky quartz or jasper (Tentatively quartz (SiO₂), possibly smoky quartz; exact identification requires testing) — mineral

Polished brown stone, likely smoky quartz or jasper

Tentatively quartz (SiO₂), possibly smoky quartz; exact identification requires testing

Limestone (Limestone (CaCO3)) — sedimentary

Limestone

Limestone (CaCO3)

Pyrite (Fool's Gold) (Iron Disulfide (FeS2)) — mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)