Rock Identifier

Category

Sedimentary (Volcanic)

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

Pegmatite (with smoky quartz and tourmaline/biotite) (Pegmatitic Granite) — igneous

Pegmatite (with smoky quartz and tourmaline/biotite)

Pegmatitic Granite

Basalt (Basalt) — igneous

Basalt

Basalt

Greenschist / Greenstone (Greenschist facies metabasite) — metamorphic

Greenschist / Greenstone

Greenschist facies metabasite

Obsidian (Obsidian (Amorphous volcanic glass, SiO2 rich)) — igneous

Obsidian

Obsidian (Amorphous volcanic glass, SiO2 rich)

Obsidian (Volcanic glass (SiO2 - Silicon Dioxide with impurities)) — igneous

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Hag Stone (Siltstone or Fine-grained Sandstone with boring (e.g., Lithophaga impact)) — sedimentary

Hag Stone

Siltstone or Fine-grained Sandstone with boring (e.g., Lithophaga impact)

River Rock (Basalt) (Basalt (SiO2 range: 45-52%)) — igneous

River Rock (Basalt)

Basalt (SiO2 range: 45-52%)

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Basalt (River Pebble) (Basalt (Aphanitic Mafic Volcanic Rock)) — Igneous

Basalt (River Pebble)

Basalt (Aphanitic Mafic Volcanic Rock)

Obsidian (Volcanic glass (SiO2 - Silicon Dioxide)) — igneous

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide)

Pumice (Pumice (a volcanic glass, primarily SiO2 with Al2O3)) — igneous

Pumice

Pumice (a volcanic glass, primarily SiO2 with Al2O3)

Sandstone (Ferruginous) (Sandstone (primarily SiO2 with Iron Oxide cement)) — sedimentary

Sandstone (Ferruginous)

Sandstone (primarily SiO2 with Iron Oxide cement)

Conglomerate (Red Sandstone variety) (Clastic Sedimentary Rock (Conglomeratic Sandstone)) — sedimentary

Conglomerate (Red Sandstone variety)

Clastic Sedimentary Rock (Conglomeratic Sandstone)

Mahogany Obsidian (Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)) — igneous

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)

Chert (Chert (variant of microcrystalline quartz)) — Sedimentary

Chert

Chert (variant of microcrystalline quartz)

Carnelian Agate (Chalcedony (SiO2 with iron oxide impurities)) — mineral

Carnelian Agate

Chalcedony (SiO2 with iron oxide impurities)

Blue Calcite (Calcium Carbonate (CaCO3)) — mineral

Blue Calcite

Calcium Carbonate (CaCO3)

Orange Calcite (likely polished specimen) (Calcite) — Mineral

Orange Calcite (likely polished specimen)

Calcite

Pyrite (Iron Disulfide (FeS2)) — Mineral

Pyrite

Iron Disulfide (FeS2)

Black Obsidian (Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide) with impurities) — igneous

Black Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide) with impurities

Scoria (Scoria (Vesicular Basaltic Glass)) — Igneous

Scoria

Scoria (Vesicular Basaltic Glass)

Sodalite (Sodalite Na8(Al6Si6O24)Cl2) — mineral

Sodalite

Sodalite Na8(Al6Si6O24)Cl2

Diorite (Salt and Pepper Rock) (Diorite) — igneous

Diorite (Salt and Pepper Rock)

Diorite

Diorite (Diorite (Intermediate Plutonic Rock)) — igneous

Diorite

Diorite (Intermediate Plutonic Rock)

Diorite (Diorite (Intermediate intrusive igneous rock)) — igneous

Diorite

Diorite (Intermediate intrusive igneous rock)

Gray Agate with Druzy Quartz Geode (Cryptocrystalline Quartz (SiO2)) — mineral

Gray Agate with Druzy Quartz Geode

Cryptocrystalline Quartz (SiO2)

Diamond (in Matrix) (Carbon (C)) — mineral

Diamond (in Matrix)

Carbon (C)

Tree Agate (Silica (SiO2) with Chlorite inclusions) — mineral

Tree Agate

Silica (SiO2) with Chlorite inclusions

Diorite (Diorite (intermediate intrusive igneous rock)) — igneous

Diorite

Diorite (intermediate intrusive igneous rock)

Silver (Native Element) (Ag (Argentum) - 90% Silver, 10% Copper alloy in specimen) — mineral

Silver (Native Element)

Ag (Argentum) - 90% Silver, 10% Copper alloy in specimen

Diamond (appearing in jewelry) (Diamond (pure Carbon, C)) — mineral

Diamond (appearing in jewelry)

Diamond (pure Carbon, C)

Carnelian (Cryptocrystalline Quartz (SiO2)) — mineral

Carnelian

Cryptocrystalline Quartz (SiO2)

Blue Chalcedony (Silicon Dioxide (SiO2)) — mineral

Blue Chalcedony

Silicon Dioxide (SiO2)

Diorite (Intermediate plutonic igneous rock) — igneous

Diorite

Intermediate plutonic igneous rock

Diorite (Diorite (an intermediate intrusive igneous rock)) — igneous

Diorite

Diorite (an intermediate intrusive igneous rock)

Black Obsidian (Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)) — igneous

Black Obsidian

Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)

Agate (Fortification Agate) (Banded Chalcedony (SiO2)) — mineral

Agate (Fortification Agate)

Banded Chalcedony (SiO2)

Snowflake Obsidian (Volcanic Glass with Cristobalite inclusions (70–75% SiO2)) — Igneous

Snowflake Obsidian

Volcanic Glass with Cristobalite inclusions (70–75% SiO2)

Basalt (tumbled/river-worn) (Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)) — igneous

Basalt (tumbled/river-worn)

Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)

Basalt (Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)) — igneous

Basalt

Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)

Black Obsidian (Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)) — igneous

Black Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)

Obsidian (Obsidian (volcanic glass), predominantly Silicon Dioxide (SiO2)) — igneous

Obsidian

Obsidian (volcanic glass), predominantly Silicon Dioxide (SiO2)