Rock Identifier

Category

Sedimentary (Volcanic)

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

Pumice (Pumice (Vesicular Rhyolite/Dacite)) — igneous

Pumice

Pumice (Vesicular Rhyolite/Dacite)

Snowflake Obsidian (Obsidian with Cristobalite inclusions (Amorphous SiO2 + SiO2 inclusions)) — igneous

Snowflake Obsidian

Obsidian with Cristobalite inclusions (Amorphous SiO2 + SiO2 inclusions)

Obsidian / Volcanic Glass (Obsidian (principally SiO2, usually 70% or more)) — igneous

Obsidian / Volcanic Glass

Obsidian (principally SiO2, usually 70% or more)

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

Basalt

Basalt (Mafic Extrusive Igneous Rock)

Fire Agate (Silicon Dioxide (SiO2) with layers of Limonite/Goethite) — mineral

Fire Agate

Silicon Dioxide (SiO2) with layers of Limonite/Goethite

Amethyst (Silicon Dioxide with Iron impurities (SiO2)) — mineral

Amethyst

Silicon Dioxide with Iron impurities (SiO2)

Obsidian (Obsidian (principally SiO2, 70% or more silica)) — igneous

Obsidian

Obsidian (principally SiO2, 70% or more silica)

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

Basalt

Basalt (Mafic Extrusive Igneous Rock)

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

Scoria (Lava Rock)

Vesicular Basalt / Scoria

Porphyritic Basalt (Chinese Writing Stone) (Porphyritic Basalt with Feldspar Phenocrysts) — igneous

Porphyritic Basalt (Chinese Writing Stone)

Porphyritic Basalt with Feldspar Phenocrysts

Pumice (Highly vesicular rhyolite/dacite (Amorphous glass)) — igneous

Pumice

Highly vesicular rhyolite/dacite (Amorphous glass)

Pumice (Pumicite (fine-grained pumice), Scoria (similar origin but denser and darker, usually basaltic)) — Igneous

Pumice

Pumicite (fine-grained pumice), Scoria (similar origin but denser and darker, usually basaltic)

Basalt (Basalt (Vitreous to Aphanitic Mafic Igneous Rock)) — igneous

Basalt

Basalt (Vitreous to Aphanitic Mafic Igneous Rock)

Pumice or Scoria (Vesicular volcanic rock) — Igneous

Pumice or Scoria

Vesicular volcanic rock

Scoria (Lava Rock) (Scoria (Extrusive Igneous Rock / Mafic Silicates)) — igneous

Scoria (Lava Rock)

Scoria (Extrusive Igneous Rock / Mafic Silicates)

Pumice (Vesicular Rhyolite or Andesite (Amorphous volcanic glass)) — igneous

Pumice

Vesicular Rhyolite or Andesite (Amorphous volcanic glass)

Basalt (Basalt) — igneous

Basalt

Basalt

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

Basalt

Basalt (Mafic Aphanitic Igneous Rock)

Porphyritic Rhyolite (Red Rhyolite) (Rhyolite (Porphyry)) — igneous

Porphyritic Rhyolite (Red Rhyolite)

Rhyolite (Porphyry)

Banded Agate (likely Carnelian Agate or Sardonyx) (Agate is a common name for a microcrystalline variety of Quartz (SiO₂), specifically a form of Chalcedony.) — Sedimentary Rock (technically a variety of Chalcedony)

Banded Agate (likely Carnelian Agate or Sardonyx)

Agate is a common name for a microcrystalline variety of Quartz (SiO₂), specifically a form of Chalcedony.

Sedimentary Rock (technically a variety of Chalcedony)

Pumice (Pumice (Vesicular Felsic Glass)) — igneous

Pumice

Pumice (Vesicular Felsic Glass)

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

Carnelian

Carnelian (Silicon Dioxide, SiO2)

Scoria (Scoria (a vesicular basalt or andesite)) — igneous

Scoria

Scoria (a vesicular basalt or andesite)

Obsidian (Obsidian (Volcanic Glass)) — igneous

Obsidian

Obsidian (Volcanic Glass)

Basalt River Cobble (Basalt (Composition primarily Plagioclase Feldspar and Pyroxene)) — igneous

Basalt River Cobble

Basalt (Composition primarily Plagioclase Feldspar and Pyroxene)

Porphyritic Andesite (Intermediate Volcanic Rock - Andesite) — Igneous

Porphyritic Andesite

Intermediate Volcanic Rock - Andesite

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

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Porphyritic Rhyolite (Rhyolite (Porphyritic)) — igneous

Porphyritic Rhyolite

Rhyolite (Porphyritic)

Larimar (Pectolite (a blue variety of Pectolite)) — Mineral

Larimar

Pectolite (a blue variety of Pectolite)

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

Sandstone (Picture Sandstone)

Arenite (primarily SiO2)

Pumice (Pumicite) — igneous

Pumice

Pumicite

Tree Agate (Dendritic Agate (Silicon Dioxide - SiO2)) — mineral

Tree Agate

Dendritic Agate (Silicon Dioxide - SiO2)

Jasper in Rhyolite matrix (Silicon Dioxide (SiO2) with various inclusions in Felsic Igneous matrix) — igneous

Jasper in Rhyolite matrix

Silicon Dioxide (SiO2) with various inclusions in Felsic Igneous matrix

Tree Agate (Silicon Dioxide with Chlorite inclusions (SiO2)) — Mineral (Variety of Chalcedony)

Tree Agate

Silicon Dioxide with Chlorite inclusions (SiO2)

Mineral (Variety of Chalcedony)

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

Basalt

Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)

Amygdaloidal Basalt (Amygdaloidal Basalt (extrusive volcanic rock with secondary mineral infilling)) — igneous

Amygdaloidal Basalt

Amygdaloidal Basalt (extrusive volcanic rock with secondary mineral infilling)

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

Basalt Pebble

Basalt (Mafic volcanic rock)

Mudstone (Lutylite (group of fine-grained sedimentary rocks)) — sedimentary

Mudstone

Lutylite (group of fine-grained sedimentary rocks)

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

Basalt

Basalt (Mafic Extrusive Igneous Rock)

Amygdaloidal Basalt (Amygdaloidal Basalt (Mafic Extrusive)) — igneous

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic Extrusive)

Olivine (often within Peridotite) (Magnesium iron silicate, (Mg,Fe)2SiO4) — mineral

Olivine (often within Peridotite)

Magnesium iron silicate, (Mg,Fe)2SiO4

Basalt with Magnetite inclusions (Basalt (Mafic silicate rock) potentially containing Magnetite (Fe3O4)) — igneous

Basalt with Magnetite inclusions

Basalt (Mafic silicate rock) potentially containing Magnetite (Fe3O4)