Rock Identifier

Category

Sedimentary (Volcanic)

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

Basalt (Weathered Pebble) (Extrusive mafic igneous rock; minerals primarily Plagioclase feldspar and Pyroxene) — igneous

Basalt (Weathered Pebble)

Extrusive mafic igneous rock; minerals primarily Plagioclase feldspar and Pyroxene

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

Basalt (River Cobble)

Basalt (Mafic Extrusive Igneous Rock)

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

Pumice

Vesicular Rhyolite or Dacite Pumice (Amorphous volcanic glass)

Basalt with Plagioclase Phenocrysts (Porphyritic Basalt) (Porphyritic Basalt (primarily Plagioclase Feldspar, Pyroxene, and Olivine)) — igneous

Basalt with Plagioclase Phenocrysts (Porphyritic Basalt)

Porphyritic Basalt (primarily Plagioclase Feldspar, Pyroxene, and Olivine)

Porphyritic Basalt (with Pyrolusite or Iron-oxide staining) (Porphyritic Basalt (Mafic Extrusive)) — igneous

Porphyritic Basalt (with Pyrolusite or Iron-oxide staining)

Porphyritic Basalt (Mafic Extrusive)

Basalt (Basalt) — igneous

Basalt

Basalt

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

Basalt River Stone

Extrusive Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)

Amygdaloidal Basalt (Amygdaloidal Basalt (Host rock) with Quartz or Calcite amygdules) — igneous

Amygdaloidal Basalt

Amygdaloidal Basalt (Host rock) with Quartz or Calcite amygdules

Amygdaloidal Basalt (Amygdaloidal Basalt with Secondary Infilling (e.g., Agate, Quartz, or Zeolite)) — igneous

Amygdaloidal Basalt

Amygdaloidal Basalt with Secondary Infilling (e.g., Agate, Quartz, or Zeolite)

Vesicular Basalt (Extrusive Mafic Igneous Rock) — igneous

Vesicular Basalt

Extrusive Mafic Igneous Rock

Amygdaloidal Basalt (Basalt with Secondary Mineral Infillings) — igneous

Amygdaloidal Basalt

Basalt with Secondary Mineral Infillings

Amethyst and Peridot (Amethyst (SiO2 with iron impurities) and Peridot ((Mg, Fe)2SiO4)) — mineral

Amethyst and Peridot

Amethyst (SiO2 with iron impurities) and Peridot ((Mg, Fe)2SiO4)

Amethyst (Polished Point) (Crystalline Quartz (SiO2 with iron impurities)) — mineral

Amethyst (Polished Point)

Crystalline Quartz (SiO2 with iron impurities)

Ocean Jasper Mushroom (Orbicular Jasper (Silicon Dioxide, SiO2 mixed with various impurities)) — mineral

Ocean Jasper Mushroom

Orbicular Jasper (Silicon Dioxide, SiO2 mixed with various impurities)

Banded Agate (Silicon Dioxide (SiO2)) — mineral

Banded Agate

Silicon Dioxide (SiO2)

Obsidian (Obsidian (principally SiO2 silicon dioxide)) — igneous

Obsidian

Obsidian (principally SiO2 silicon dioxide)

Vesicular Basalt (Scoria) (Vesicular Basalt) — igneous

Vesicular Basalt (Scoria)

Vesicular Basalt

Ocean Jasper (Spherulitic Chalcedony (SiO2)) — mineral

Ocean Jasper

Spherulitic Chalcedony (SiO2)

Unknown Rock Specimen — igneous

Unknown Rock Specimen

Basalt (Extrusive Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)) — igneous

Basalt

Extrusive Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)

Scoria (Lava Rock) (Scoria (extrusive volcanic rock)) — igneous

Scoria (Lava Rock)

Scoria (extrusive volcanic rock)

Amygdaloidal Basalt (Amygdaloidal Basalt (Ca-rich Plagioclase, Pyroxene, and Olivine)) — igneous

Amygdaloidal Basalt

Amygdaloidal Basalt (Ca-rich Plagioclase, Pyroxene, and Olivine)

Amethyst Geode (Thunderegg) (Silicon Dioxide (SiO2) - Quartz Variety: Amethyst) — mineral

Amethyst Geode (Thunderegg)

Silicon Dioxide (SiO2) - Quartz Variety: Amethyst

Quartz (Quartz (SiO₂)) — Mineral

Quartz

Quartz (SiO₂)

Leopard Skin Jasper (Chalcedony (cryptocrystalline Quartz)) — Mineral

Leopard Skin Jasper

Chalcedony (cryptocrystalline Quartz)

Halite (Halite (NaCl)) — Mineral

Halite

Halite (NaCl)

Agate (Silicon Dioxide (SiO2)) — mineral

Agate

Silicon Dioxide (SiO2)

Clay (as a rock-forming material) (Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)) — Mineral

Clay (as a rock-forming material)

Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)

Jasper (Milky/Cream Variety) (Silicon Dioxide (SiO2) - variety of Chalcedony) — sedimentary (chemical/biological)

Jasper (Milky/Cream Variety)

Silicon Dioxide (SiO2) - variety of Chalcedony

sedimentary (chemical/biological)

Amygdaloidal Basalt (Amygdaloidal Basalt (Mafic volcanic rock with secondary mineral fillings)) — igneous

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic volcanic rock with secondary mineral fillings)

Amethyst (Silicon dioxide (variant with ferric iron impurities), SiO2) — mineral

Amethyst

Silicon dioxide (variant with ferric iron impurities), SiO2

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

Fire Opal (in Matrix)

Hydrated Silica (SiO2·nH2O)

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

Basalt Pebble

Basalt (Mafic Extrusive Igneous Rock)

Scoria (Vesicular Basalt / Scoria) — igneous

Scoria

Vesicular Basalt / Scoria

Vesicular Basalt with Amygdaloidal Infill (Basalt (Mafic Extrusive Igneous Rock)) — igneous

Vesicular Basalt with Amygdaloidal Infill

Basalt (Mafic Extrusive Igneous Rock)

Basalt (Basalt) — igneous

Basalt

Basalt

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

Basalt Pebble

Basalt (Aphanitic Mafic Igneous Rock)

Olivine in Basalt (Peridotite Xenolith) (Forsterite-rich Olivine (Mg2SiO4) in Aphanitic Basalt) — igneous

Olivine in Basalt (Peridotite Xenolith)

Forsterite-rich Olivine (Mg2SiO4) in Aphanitic Basalt

Vesicular Basalt (Iron-rich) (Scoriaceous Basalt / Oxidized Vesicular Basalt) — igneous

Vesicular Basalt (Iron-rich)

Scoriaceous Basalt / Oxidized Vesicular Basalt

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

Basalt (Vesicular)

Basalt (Extrusive Mafic Igneous Rock)

Vesicular Basalt (Amygdaloidal Basalt (Mafic extrusive volcanic rock)) — Igneous

Vesicular Basalt

Amygdaloidal Basalt (Mafic extrusive volcanic rock)

Scoria (Volcanic Rock) (Scoria (often basaltic scoria)) — Igneous

Scoria (Volcanic Rock)

Scoria (often basaltic scoria)