Rock Identifier

Category

Sedimentary (Volcanic)

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

Flesh-toned Siltstone (Siltstone (composed of microscopic Quartz and Feldspar grains)) — sedimentary

Flesh-toned Siltstone

Siltstone (composed of microscopic Quartz and Feldspar grains)

Porphyritic Rhyolite (Porphyritic Rhyolite (compositionally similar to granite)) — igneous

Porphyritic Rhyolite

Porphyritic Rhyolite (compositionally similar to granite)

Porphyritic Andesite (Andesite (porphyritic variety)) — igneous

Porphyritic Andesite

Andesite (porphyritic variety)

Olivine in Basalt (Peridotite / Forsterite ((Mg,Fe)2SiO4)) — igneous

Olivine in Basalt

Peridotite / Forsterite ((Mg,Fe)2SiO4)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Shale (Shale (fine-grained clastic sedimentary rock)) — Sedimentary

Shale

Shale (fine-grained clastic sedimentary rock)

Jasper in Basalt Matrix (Silicon Dioxide (SiO2) with impurities; Chalcedony) — sedimentary (secondary mineral) within igneous

Jasper in Basalt Matrix

Silicon Dioxide (SiO2) with impurities; Chalcedony

sedimentary (secondary mineral) within igneous

Obsidian (Obsidian (principally SiO2 + MgO, Fe3O4)) — igneous

Obsidian

Obsidian (principally SiO2 + MgO, Fe3O4)

Mahogany Obsidian (Volcanic Glass with Hematite/Magnetite inclusions (SiO2)) — igneous

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2)

Vesicular Basalt with Secondary Mineral Infill (Mafic Volcanic Rock (Basalt)) — igneous

Vesicular Basalt with Secondary Mineral Infill

Mafic Volcanic Rock (Basalt)

Basalt Pebble (Extrusive Mafic Volcanic Rock) — igneous

Basalt Pebble

Extrusive Mafic Volcanic Rock

Basalt Pebble (Basalt (Mafic volcanic rock)) — igneous

Basalt Pebble

Basalt (Mafic volcanic rock)

Agate (Agate (Silicon Dioxide, SiO2)) — mineral

Agate

Agate (Silicon Dioxide, SiO2)

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

Banded Agate

Agate (Silicon Dioxide - SiO2)

Basalt (Basalt (Aphanitic Mafic Volcanic Rock)) — igneous

Basalt

Basalt (Aphanitic Mafic Volcanic Rock)

Pink Opal / Peruvian Opal (Hydrated amorphous silicon dioxide (SiO2·nH2O)) — Mineral

Pink Opal / Peruvian Opal

Hydrated amorphous silicon dioxide (SiO2·nH2O)

Porphyritic Andesite (Andesite) — igneous

Porphyritic Andesite

Andesite

Sandstone (Clastic sedimentary rock (primarily SiO2)) — sedimentary

Sandstone

Clastic sedimentary rock (primarily SiO2)

Shale with Siltstone layering (Sedimentary Clastic Rock (Mudstone/Shale)) — sedimentary

Shale with Siltstone layering

Sedimentary Clastic Rock (Mudstone/Shale)

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

Sandstone (Quartz Sandstone)

Arenite (primarily SiO2)

Red Jasper (Jasper (a variety of Chalcedony, SiO₂ with impurities)) — Mineral

Red Jasper

Jasper (a variety of Chalcedony, SiO₂ with impurities)

Banded Agate (variety of Chalcedony) (Agate (SiO2)) — mineral

Banded Agate (variety of Chalcedony)

Agate (SiO2)

Banded Gneiss (Gneiss (pronounced "nice")) — metamorphic

Banded Gneiss

Gneiss (pronounced "nice")

Ocean Jasper (Orbicular Jasper) (Silicon Dioxide (SiO2)) — Sedimentary Rock

Ocean Jasper (Orbicular Jasper)

Silicon Dioxide (SiO2)

Sedimentary Rock

Chalcedony (or a variety of Chalcedony, likely Agate or Jasper) (Chalcedony (SiO₂)) — Mineral (or mineraloid if microcrystalline)

Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)

Chalcedony (SiO₂)

Mineral (or mineraloid if microcrystalline)

Diorite (Diorite) — igneous

Diorite

Diorite

Pumice (Pumice (a highly vesicular extrusive igneous rock)) — igneous

Pumice

Pumice (a highly vesicular extrusive igneous rock)

Basalt (Beach Pebble) (Extrusive mafic volcanic rock) — igneous

Basalt (Beach Pebble)

Extrusive mafic volcanic rock

Basalt (Vesicular or Scoriaceous) (Aphanitic Mafic Volcanic Rock) — igneous

Basalt (Vesicular or Scoriaceous)

Aphanitic Mafic Volcanic Rock

Obsidian (Amorphous volcanic glass (SiO2)) — igneous

Obsidian

Amorphous volcanic glass (SiO2)

Obsidian (Volcanic Glass (SiO2 + impurities)) — igneous

Obsidian

Volcanic Glass (SiO2 + impurities)

Obsidian (Volcanic Glass (mostly SiO2)) — igneous

Obsidian

Volcanic Glass (mostly SiO2)

Limonite with Trace Fossils (Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)) — sedimentary

Limonite with Trace Fossils

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

Chalcedony (Chalcedony (SiO₂)) — Mineral

Chalcedony

Chalcedony (SiO₂)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Sedimentary Breccia (Breccia (Clastic Sedimentary Rock)) — sedimentary

Sedimentary Breccia

Breccia (Clastic Sedimentary Rock)

Sedimentary Breccia (Clastic Breccia (CaCO3/SiO2 matrix)) — sedimentary

Sedimentary Breccia

Clastic Breccia (CaCO3/SiO2 matrix)

Moqui Marble (Concretion) (Iron Oxide Concretion (Hematite-cemented Sandstone)) — sedimentary

Moqui Marble (Concretion)

Iron Oxide Concretion (Hematite-cemented Sandstone)

Scoria (Extrusive Basaltic Scoria) — igneous

Scoria

Extrusive Basaltic Scoria

Scoria (Vesicular Basalt / Scoria (Mafic volcanic rock)) — igneous

Scoria

Vesicular Basalt / Scoria (Mafic volcanic rock)

Snowflake Obsidian (Volcanic glass containing Spherulites (SiO2)) — igneous

Snowflake Obsidian

Volcanic glass containing Spherulites (SiO2)