Rock Identifier

Category

Igneous Rock (Volcanic Glass)

Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.

Carnelian Agate (Silicon Dioxide (SiO2) - Variety: Chalcedony) — mineral

Carnelian Agate

Silicon Dioxide (SiO2) - Variety: Chalcedony

Quartz Druse (on Chalcedony/Agate base) (Silicon Dioxide (SiO2)) — mineral

Quartz Druse (on Chalcedony/Agate base)

Silicon Dioxide (SiO2)

Porphyritic Andesite (often called Chinese Writing Stone) (Porphyritic Basaltic Andesite with Feldspar Phenocrysts) — igneous

Porphyritic Andesite (often called Chinese Writing Stone)

Porphyritic Basaltic Andesite with Feldspar Phenocrysts

Agate (specifically Carnelian or Honey Agate) (Silicon Dioxide (SiO2)) — Mineral

Agate (specifically Carnelian or Honey Agate)

Silicon Dioxide (SiO2)

Obsidian with Spherulitic Devitrification (Snowflake Obsidian/Mahogany related) (Volcanic Glass (70% or more SiO2)) — igneous

Obsidian with Spherulitic Devitrification (Snowflake Obsidian/Mahogany related)

Volcanic Glass (70% or more SiO2)

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

Obsidian

Obsidian (Amorphous volcanic glass, predominantly SiO2)

White Quartz Pebble (Silicon Dioxide (SiO2)) — mineral

White Quartz Pebble

Silicon Dioxide (SiO2)

Amethyst (Tumbled Chips) (Amethyst (Silicon Dioxide with Iron impurities, SiO2)) — mineral

Amethyst (Tumbled Chips)

Amethyst (Silicon Dioxide with Iron impurities, SiO2)

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

Obsidian

Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)

Obsidian (Volcanic Glass (Primary component: SiO2)) — igneous

Obsidian

Volcanic Glass (Primary component: SiO2)

Amethyst (Druze) (Silicon Dioxide (SiO2) with iron impurities) — mineral

Amethyst (Druze)

Silicon Dioxide (SiO2) with iron impurities

Amethyst (Silicon Dioxide (SiO2) with traces of Iron and Manganese) — mineral

Amethyst

Silicon Dioxide (SiO2) with traces of Iron and Manganese

Quartz (Common Milky Quartz) (Silicon Dioxide (SiO2)) — mineral

Quartz (Common Milky Quartz)

Silicon Dioxide (SiO2)

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + oxide impurities)

Druzy Quartz on Agate/Chert (Silicon Dioxide (SiO2)) — mineral

Druzy Quartz on Agate/Chert

Silicon Dioxide (SiO2)

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

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Milky Quartz (Quartz / Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Quartz / Silicon Dioxide (SiO2)

Blue Chalcedony (Silicon Dioxide (SiO2)) — mineral

Blue Chalcedony

Silicon Dioxide (SiO2)

Black Obsidian with white veins (Volcanic Glass (70–75% SiO2)) — igneous

Black Obsidian with white veins

Volcanic Glass (70–75% SiO2)

Milky Quartz with Iron Inclusions (Silicon Dioxide (SiO2)) — mineral

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Amethyst Quartz (Silicon Dioxide (SiO2) with iron impurities) — mineral

Amethyst Quartz

Silicon Dioxide (SiO2) with iron impurities

Granite (Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)) — igneous

Granite

Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)

Jasper (brecciated or orbicular variety) (Silicon dioxide (SiO2) with iron oxide inclusions) — sedimentary/mineral

Jasper (brecciated or orbicular variety)

Silicon dioxide (SiO2) with iron oxide inclusions

sedimentary/mineral

Aquamarine (Beryl (Be3Al2Si6O18 with trace Fe2+)) — mineral

Aquamarine

Beryl (Be3Al2Si6O18 with trace Fe2+)

Milky Quartz (Silicon Dioxide (SiO₂)) — Mineral

Milky Quartz

Silicon Dioxide (SiO₂)

Milky Quartz (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Granodiorite (or Granite) Pebble (Phaneritic Felsic Igneous Pebble) — igneous

Granodiorite (or Granite) Pebble

Phaneritic Felsic Igneous Pebble

Apache Tears (Obsidian) (Hydrated Volcanic Glass (Amorphous SiO2 + H2O)) — igneous

Apache Tears (Obsidian)

Hydrated Volcanic Glass (Amorphous SiO2 + H2O)

Diorite (Salt and Pepper Rock) (Phaneritic Plutonic Diorite (Plagioclase Feldspar + Amphibole/Biotite)) — igneous

Diorite (Salt and Pepper Rock)

Phaneritic Plutonic Diorite (Plagioclase Feldspar + Amphibole/Biotite)

Smoky Quartz (Silicon Dioxide (SiO2)) — mineral

Smoky Quartz

Silicon Dioxide (SiO2)

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

Amethyst

SiO2 (Silicon Dioxide with Iron impurities)

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

Apache Tear (Obsidian)

Volcanic glass (SiO2 - Silicon Dioxide)

Obsidian (Obsidian (Volcanic Glass), primarily SiO2) — igneous

Obsidian

Obsidian (Volcanic Glass), primarily SiO2

Black Obsidian (Volcanic Glass (SiO2 + impurities like Fe3O4)) — igneous

Black Obsidian

Volcanic Glass (SiO2 + impurities like Fe3O4)

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

Black Obsidian

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

Pink Granite (Crystalline Granite) (Igneous Intrusive Rock (Felsic Plutonic)) — igneous

Pink Granite (Crystalline Granite)

Igneous Intrusive Rock (Felsic Plutonic)

Snowflake Obsidian (Vitreous Volcanic Glass (Siliceous Obsidian with Cristobalite inclusions)) — igneous

Snowflake Obsidian

Vitreous Volcanic Glass (Siliceous Obsidian with Cristobalite inclusions)

Obsidian Arrowhead (Volcanic Glass (70% or more SiO2)) — Igneous

Obsidian Arrowhead

Volcanic Glass (70% or more SiO2)

Milky Quartz (Quartz (Silicon Dioxide - SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Jasper (Silicon dioxide (SiO2) with impurities) — sedimentary

Jasper

Silicon dioxide (SiO2) with impurities

Ferruginous Quartz Cobble (Silicon Dioxide (SiO2) with Iron Oxide inclusions) — mineral

Ferruginous Quartz Cobble

Silicon Dioxide (SiO2) with Iron Oxide inclusions