Rock Identifier

Category

Sedimentary (Volcanic)

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

Porphyritic Andesite (Andesite (Porphyry)) — igneous

Porphyritic Andesite

Andesite (Porphyry)

Slag Glass (Vitreous Silicate Residue) — industrial byproduct (anthropogenic rock)

Slag Glass

Vitreous Silicate Residue

industrial byproduct (anthropogenic rock)

Scoria (Lava Rock) (Mafic extrusive volcanic rock (Scientific formula varies based on mineral content: primarily SiO2, MgO, and FeO)) — igneous

Scoria (Lava Rock)

Mafic extrusive volcanic rock (Scientific formula varies based on mineral content: primarily SiO2, MgO, and FeO)

River Cobble (likely Basalt or Rhyolite) (Extrusive Igneous Rock (Mafic or Intermediate)) — igneous

River Cobble (likely Basalt or Rhyolite)

Extrusive Igneous Rock (Mafic or Intermediate)

Quartz on Basalt (Silicon Dioxide (SiO2) on Mafic Igneous Rock) — Mineral on Igneous Rock

Quartz on Basalt

Silicon Dioxide (SiO2) on Mafic Igneous Rock

Mineral on Igneous Rock

Pumice (Vesicular volcanic glass (Amorphous silica mixed with various oxides)) — igneous

Pumice

Vesicular volcanic glass (Amorphous silica mixed with various oxides)

Limonite (Ironstone Concretion) (Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)) — mineral

Limonite (Ironstone Concretion)

Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)

Obsidian (Volcanic glass (mainly SiO2)) — Igneous

Obsidian

Volcanic glass (mainly SiO2)

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

Black Obsidian

Volcanic Glass (SiO2 + impurities)

Basalt (with Brass Inlay) (Basalt (Mafic volcanic rock)) — igneous

Basalt (with Brass Inlay)

Basalt (Mafic volcanic rock)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Basalt with Weathering Crust (Extrusive mafic volcanic rock) — igneous

Basalt with Weathering Crust

Extrusive mafic volcanic rock

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

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

Vesicular Basalt

Mafic Volcanic Rock (Basalt)

Obsidian (Volcanic Glass (predominantly SiO2)) — igneous

Obsidian

Volcanic Glass (predominantly SiO2)

Snowflake Obsidian (Volcanic Glass with Cristobalite inclusions) — igneous

Snowflake Obsidian

Volcanic Glass with Cristobalite inclusions

Apache Tear (Hydrated Obsidian (Volcanic Glass)) — igneous

Apache Tear

Hydrated Obsidian (Volcanic Glass)

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

Obsidian

Volcanic Glass (SiO2 + impurities)

Amygdaloidal Basalt (Amygdaloidal Mafic Volcanic Rock) — igneous

Amygdaloidal Basalt

Amygdaloidal Mafic Volcanic Rock

Obsidian (Volcanic Glass (predominantly SiO2)) — igneous

Obsidian

Volcanic Glass (predominantly SiO2)

Black Obsidian (Volcanic Glass (SiO2 + impurities)) — Igneous

Black Obsidian

Volcanic Glass (SiO2 + impurities)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Basalt Pebble with Quartz Veining (Basalt (extrusive volcanic rock)) — igneous

Basalt Pebble with Quartz Veining

Basalt (extrusive volcanic rock)

Basalt (Basalt (extrusive volcanic rock)) — igneous

Basalt

Basalt (extrusive volcanic rock)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Basalt River Stone (Basalt (Mafic volcanic rock)) — igneous

Basalt River Stone

Basalt (Mafic volcanic rock)

Basalt (Vesicular) (Basalt (Extrusive Volcanic Rock)) — igneous

Basalt (Vesicular)

Basalt (Extrusive Volcanic Rock)

Apache Tear (Obsidian (Hydrated Volcanic Glass)) — igneous

Apache Tear

Obsidian (Hydrated Volcanic Glass)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Obsidian (specifically Rainbow or Silver Sheen Obsidian) (Volcanic Glass (predominantly SiO2)) — Igneous

Obsidian (specifically Rainbow or Silver Sheen Obsidian)

Volcanic Glass (predominantly SiO2)

Basalt (Basalt (Aphanitic Mafic Volcanic)) — igneous

Basalt

Basalt (Aphanitic Mafic Volcanic)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Andesite Porphyry (Andesite (extrusive volcanic rock)) — igneous

Andesite Porphyry

Andesite (extrusive volcanic rock)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Mahogany Obsidian (Volcanic Glass (SiO2 + Fe2O3)) — igneous

Mahogany Obsidian

Volcanic Glass (SiO2 + Fe2O3)

Pumice (Pumice (volcanic glass froth)) — igneous

Pumice

Pumice (volcanic glass froth)

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

Scoria (Lava Rock)

Scoria (extrusive volcanic rock)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Black Obsidian (Volcanic Glass (predominantly SiO2)) — igneous

Black Obsidian

Volcanic Glass (predominantly SiO2)