Rock Identifier

Category

Sedimentary (Volcanic)

Browse sedimentary (volcanic) specimens identified by the Rock Identifier community.

Sandstone (Quartzose) (Arenite (primarily SiO2)) — sedimentary

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone Concretion (Clastic sedimentary rock (primarily Silica, SiO2, or Calcium Carbonate, CaCO3)) — sedimentary

Sandstone Concretion

Clastic sedimentary rock (primarily Silica, SiO2, or Calcium Carbonate, CaCO3)

Chert (often called Flint) (Chert (Cryptocrystalline Quartz, SiO2)) — sedimentary

Chert (often called Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Sandstone (likely Arkose or Quartz Sandstone) (Arenite (SiO2 + varied clasts)) — sedimentary

Sandstone (likely Arkose or Quartz Sandstone)

Arenite (SiO2 + varied clasts)

Piddock bored rock (likely Mudstone or Shale) (Ichnofossil (Gastrochaenolites borings) in Fine-grained Sedimentary Rock) — sedimentary

Piddock bored rock (likely Mudstone or Shale)

Ichnofossil (Gastrochaenolites borings) in Fine-grained Sedimentary Rock

Mahogany Obsidian (Obsidian (Volcanic Glass) with Hematite or Magnetite inclusions, SiO2 (Silicon Dioxide)) — igneous

Mahogany Obsidian

Obsidian (Volcanic Glass) with Hematite or Magnetite inclusions, SiO2 (Silicon Dioxide)

Basalt (Mafic volcanic rock (formula varies by mineral content: Ca-plagioclase, Pyroxene, Olivine)) — igneous

Basalt

Mafic volcanic rock (formula varies by mineral content: Ca-plagioclase, Pyroxene, Olivine)

Quartz (Quartz (SiO2 - Silicon Dioxide)) — Mineral

Quartz

Quartz (SiO2 - Silicon Dioxide)

Scoria (Vesicular Basalt) (Scoria (Vesicular Igneous Rock)) — igneous

Scoria (Vesicular Basalt)

Scoria (Vesicular Igneous Rock)

Conglomerate (Conglomerate (clastic sedimentary rock)) — sedimentary

Conglomerate

Conglomerate (clastic sedimentary rock)

Basalt (Basalt (primarily composed of Plagioclase feldspar and Pyroxene)) — igneous

Basalt

Basalt (primarily composed of Plagioclase feldspar and Pyroxene)

Amethyst Geode (Amethyst (Silicon Dioxide), Formula: SiO2) — mineral

Amethyst Geode

Amethyst (Silicon Dioxide), Formula: SiO2

Banded Agate (Pink/Peach Chalcedony) (Agate (Silicon Dioxide, SiO2)) — mineral

Banded Agate (Pink/Peach Chalcedony)

Agate (Silicon Dioxide, SiO2)

Celestite (Celestine) Geode (Strontium Sulfate (SrSO4)) — mineral

Celestite (Celestine) Geode

Strontium Sulfate (SrSO4)

Stromatolite (Stromatolite (Cyanobacteria-formed Organo-sedimentary structure)) — sedimentary

Stromatolite

Stromatolite (Cyanobacteria-formed Organo-sedimentary structure)

Coal (Bituminous or Anthracite) (Carbonaceous sedimentary rock (primarily Carbon, C)) — sedimentary

Coal (Bituminous or Anthracite)

Carbonaceous sedimentary rock (primarily Carbon, C)

Sandstone (Ferruginous) (Arenite (Fe-bearing Clastic Sedimentary Rock)) — sedimentary

Sandstone (Ferruginous)

Arenite (Fe-bearing Clastic Sedimentary Rock)

Sandstone (Arenite or Sandstone) — Sedimentary Rock

Sandstone

Arenite or Sandstone

Sedimentary Rock

Sandstone (with potential fossil inclusions) (Clastic sedimentary rock (primarily SiO2)) — sedimentary

Sandstone (with potential fossil inclusions)

Clastic sedimentary rock (primarily SiO2)

Banded Agate (specifically Lace Agate type) (Silicon Dioxide (SiO2)) — mineral

Banded Agate (specifically Lace Agate type)

Silicon Dioxide (SiO2)

Basalt with Vesicles (Vesicular Basalt (comprising Plagioclase Feldspar, Pyroxene, and Olivine)) — igneous

Basalt with Vesicles

Vesicular Basalt (comprising Plagioclase Feldspar, Pyroxene, and Olivine)

Sandstone (Arenite) — sedimentary

Sandstone

Arenite

Sandstone (Weathered Pebble) (Arenite (composed primarily of SiO2)) — sedimentary

Sandstone (Weathered Pebble)

Arenite (composed primarily of SiO2)

Blue Moss Agate / Blue Chalcedony (Silicon Dioxide (SiO2)) — mineral

Blue Moss Agate / Blue Chalcedony

Silicon Dioxide (SiO2)

Basalt (with possible mineral veining) (Basalt (Aphanitic Mafic Igneous Rock)) — Igneous

Basalt (with possible mineral veining)

Basalt (Aphanitic Mafic Igneous Rock)

Ethiopian Opal (Welo Opal in Matrix) (Hydrated Silica (SiO2·nH2O)) — mineral

Ethiopian Opal (Welo Opal in Matrix)

Hydrated Silica (SiO2·nH2O)

Drupa Quartz (Sparkly Drusy Quartz on Matrix) (Crystalline Silicon Dioxide (SiO2) on host rock) — mineral

Drupa Quartz (Sparkly Drusy Quartz on Matrix)

Crystalline Silicon Dioxide (SiO2) on host rock

Scoria with Calcite Infills (Vesicular Basalt with secondary Calcification (CaCO3)) — igneous

Scoria with Calcite Infills

Vesicular Basalt with secondary Calcification (CaCO3)

Basalt River Pebble (Basalt) — igneous

Basalt River Pebble

Basalt

Basalt (Extrusive mafic igneous rock) — igneous

Basalt

Extrusive mafic igneous rock

Granite (Granite (Felsic Plutonic Rock)) — igneous

Granite

Granite (Felsic Plutonic Rock)

Amethyst (Tumbled) (Silicon Dioxide with iron impurities (SiO2)) — mineral

Amethyst (Tumbled)

Silicon Dioxide with iron impurities (SiO2)

Obsidian (Obsidian (principally SiO2)) — igneous

Obsidian

Obsidian (principally SiO2)

Scoria (Lava Rock) (Scoriaceous Basalt) — igneous

Scoria (Lava Rock)

Scoriaceous Basalt

Basalt (Basalt (Mafic Extrusive)) — igneous

Basalt

Basalt (Mafic Extrusive)

Basalt with Scoria and potential Olivine/Pyroxene inclusions (Vesicular Basalt) — igneous

Basalt with Scoria and potential Olivine/Pyroxene inclusions

Vesicular Basalt

Native Gold Nugget (Native Gold (Au)) — mineral

Native Gold Nugget

Native Gold (Au)

Basalt (Mafic Igneous Rock (composed primarily of Plagioclase and Pyroxene)) — igneous

Basalt

Mafic Igneous Rock (composed primarily of Plagioclase and Pyroxene)

Basalt (Vesicular/Scoria) (Vesicular Basalt) — igneous

Basalt (Vesicular/Scoria)

Vesicular Basalt

Basalt (Basalt) — igneous

Basalt

Basalt

Basalt (Basalt (predominantly Plagioclase Feldspar and Pyroxene)) — igneous

Basalt

Basalt (predominantly Plagioclase Feldspar and Pyroxene)

Basalt (Basalt (Mafic Extrusive Igneous Rock)) — igneous

Basalt

Basalt (Mafic Extrusive Igneous Rock)