Rock Identifier

Category

Organic (Geological Interest)

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

Sedimentary rock with quartz veining (Laminated siltstone or mudstone with hydrothermal quartz veins) — sedimentary

Sedimentary rock with quartz veining

Laminated siltstone or mudstone with hydrothermal quartz veins

Quartz Vein in Host Rock (Silicon Dioxide (SiO2)) — mineral with metamorphic or sedimentary host

Quartz Vein in Host Rock

Silicon Dioxide (SiO2)

mineral with metamorphic or sedimentary host

Conglomerate (Conglomerate (clastic sedimentary rock)) — sedimentary

Conglomerate

Conglomerate (clastic sedimentary rock)

Sandstone with Vitrinite/Coal inclusions (Arenite with Carbonaceous inclusions) — sedimentary

Sandstone with Vitrinite/Coal inclusions

Arenite with Carbonaceous inclusions

Chert (within Limestone) (Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3) matrix) — sedimentary

Chert (within Limestone)

Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3) matrix

Chert (Iron-stained) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Biotite Schist (Biotite Mica Schist) — metamorphic

Biotite Schist

Biotite Mica Schist

Puddingstone (Conglomerate (Silicon Dioxide - SiO2 with various inclusions)) — sedimentary

Puddingstone

Conglomerate (Silicon Dioxide - SiO2 with various inclusions)

Chert Breccia (Brecciated Chert) — sedimentary

Chert Breccia

Brecciated Chert

Limonite on Sandstone (Iron Oxyhydroxide (FeO(OH)·nH2O) on Quartz Sandstone) — sedimentary

Limonite on Sandstone

Iron Oxyhydroxide (FeO(OH)·nH2O) on Quartz Sandstone

Earthy Siltstone with Iron Staining (Siltstone / Argillite with Goethite/Hematite inclusions) — sedimentary

Earthy Siltstone with Iron Staining

Siltstone / Argillite with Goethite/Hematite inclusions

Concretion (Septarian or Siderite Concretion) — sedimentary

Concretion

Septarian or Siderite Concretion

Phyllite with Quartz Vein (Metamorphic Phyllite) — metamorphic

Phyllite with Quartz Vein

Metamorphic Phyllite

Greenschist (Greenschist (Chlorite-actinolite schist)) — metamorphic

Greenschist

Greenschist (Chlorite-actinolite schist)

Ocellar Rhyolite (Rhyolite (featuring orbicular/ocellar quartz and feldspar textures)) — igneous

Ocellar Rhyolite

Rhyolite (featuring orbicular/ocellar quartz and feldspar textures)

Xenolith in Basalt (Mafic Igneous Rock with Felsic Inclusion) — igneous

Xenolith in Basalt

Mafic Igneous Rock with Felsic Inclusion

Sandstone Concretion (Septarian Concretion (Nodule)) — sedimentary

Sandstone Concretion

Septarian Concretion (Nodule)

Mookaite Jasper (Radiolarite (Silicified radiolarian chert), SiO2) — sedimentary

Mookaite Jasper

Radiolarite (Silicified radiolarian chert), SiO2

Tuff with Quartz and Calcite Veining (Lithic Tuff (Silicified)) — igneous

Tuff with Quartz and Calcite Veining

Lithic Tuff (Silicified)

Chert (Septarian Nodules-like) (Silicon dioxide (SiO2)) — sedimentary

Chert (Septarian Nodules-like)

Silicon dioxide (SiO2)

Porphyritic granite (likely weathered granitic rock) (Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende) — igneous

Porphyritic granite (likely weathered granitic rock)

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Peridotite Nodules in Basalt (Xenolith) (Ultramafic Xenolith (Olivine-rich Peridotite in Basalt)) — igneous

Peridotite Nodules in Basalt (Xenolith)

Ultramafic Xenolith (Olivine-rich Peridotite in Basalt)

Limonite (Limonitic Sandstone) (Hydrated Iron(III) Oxide-Hydroxide ($FeO(OH)·nH_2O$)) — sedimentary

Limonite (Limonitic Sandstone)

Hydrated Iron(III) Oxide-Hydroxide ($FeO(OH)·nH_2O$)

Schist with Quartz Vein (Mica Schist with Crystalline Quartz (SiO2)) — metamorphic

Schist with Quartz Vein

Mica Schist with Crystalline Quartz (SiO2)

Epidote (Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))) — mineral

Epidote

Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Quartz Vein in Host Rock (Silicon Dioxide (SiO2) within Metasedimentary or Igneous Matrix) — metamorphic

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Metasedimentary or Igneous Matrix

Quartz Vein in Host Rock (Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix) — igneous

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix

Basalt (Basalt (extrusive volcanic rock)) — igneous

Basalt

Basalt (extrusive volcanic rock)

Gossan (Iron Hat) (Limonitic Gossan (Fe2O3·nH2O)) — sedimentary

Gossan (Iron Hat)

Limonitic Gossan (Fe2O3·nH2O)

Vesicular Basalt (Vesicular Basalt) — igneous

Vesicular Basalt

Vesicular Basalt

Green Schist (Greenschist (Chlorite Schist)) — metamorphic

Green Schist

Greenschist (Chlorite Schist)

Epidote and Quartz in Basalt (Epidote [Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)] in Metabasalt) — metamorphic

Epidote and Quartz in Basalt

Epidote [Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)] in Metabasalt

Mica Schist with Quartz (Muscovite/Biotite Schist) — metamorphic

Mica Schist with Quartz

Muscovite/Biotite Schist

Slickenside in Limestone (Tectonized Limestone / Calcite (CaCO3)) — metamorphic (localized) or sedimentary

Slickenside in Limestone

Tectonized Limestone / Calcite (CaCO3)

metamorphic (localized) or sedimentary

Schist (Graphite or Mica rich) (Crystalline Schist (often containing Muscovite, Biotite, or Graphite)) — metamorphic

Schist (Graphite or Mica rich)

Crystalline Schist (often containing Muscovite, Biotite, or Graphite)

Lava Rock with Fabric Impression (Scoria or Basalt with anthropogenic impressions) — igneous

Lava Rock with Fabric Impression

Scoria or Basalt with anthropogenic impressions

Fossilized Wood (Petrified Wood) (Silicified Wood (primarily quartz/chalcedony replacing organic matter)) — Sedimentary (with some aspects of mineral replacement)

Fossilized Wood (Petrified Wood)

Silicified Wood (primarily quartz/chalcedony replacing organic matter)

Sedimentary (with some aspects of mineral replacement)

Basalt (River Pebble) (Basalt) — igneous

Basalt (River Pebble)

Basalt

Shale with Quartz Veins (Fissile Sedimentary Rock (SiO2)) — sedimentary

Shale with Quartz Veins

Fissile Sedimentary Rock (SiO2)

Conglomerate (Conglomerate (clastic sedimentary rock)) — sedimentary

Conglomerate

Conglomerate (clastic sedimentary rock)

Chert Conglomerate (Potomac Puddle Stone) (Sedimentary Conglomerate with Iron-Oxide matrix) — sedimentary

Chert Conglomerate (Potomac Puddle Stone)

Sedimentary Conglomerate with Iron-Oxide matrix

Sandstone (River Pebble) (Clastic Sedimentary Rock (primarily Quartz)) — sedimentary

Sandstone (River Pebble)

Clastic Sedimentary Rock (primarily Quartz)