Rock Identifier

Category

Volcanic Glass (Igneous)

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

Learn about Volcanic Glass (Igneous) in the encyclopedia

Black Obsidian

Pink Obsidian

Sideromelane

Obsidian

Tachylite

Perlite

Yellow Obsidian

Yellow Obsidian

Turquoise Obsidian

Teal Obsidian

Green Sheen Obsidian

Clear Obsidian

Cobalt Blue Obsidian

Polished mahogany obsidian (Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)) — igneous

Polished mahogany obsidian

Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)

Obsidian (likely snowflake or smoky obsidian fragment) (Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)) — igneous

Obsidian (likely snowflake or smoky obsidian fragment)

Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)

Porphyritic basaltic-andesite cobble (Fine-grained plagioclase–pyroxene volcanic rock, likely basaltic andesite) — igneous

Porphyritic basaltic-andesite cobble

Fine-grained plagioclase–pyroxene volcanic rock, likely basaltic andesite

Black obsidian (possibly industrial glass or slag) (Volcanic glass; predominantly rhyolitic composition, chiefly SiO₂) — igneous

Black obsidian (possibly industrial glass or slag)

Volcanic glass; predominantly rhyolitic composition, chiefly SiO₂

Polished black gemstone, likely black obsidian (Obsidian (volcanic glass), chiefly silica-rich amorphous SiO₂) — igneous

Polished black gemstone, likely black obsidian

Obsidian (volcanic glass), chiefly silica-rich amorphous SiO₂

Rhyolite (Rhyolite (High-silica volcanic rock)) — igneous

Rhyolite

Rhyolite (High-silica volcanic rock)

Likely obsidian (black volcanic glass) (Obsidian; predominantly rhyolitic volcanic glass, often ~70–75% SiO₂) — igneous

Likely obsidian (black volcanic glass)

Obsidian; predominantly rhyolitic volcanic glass, often ~70–75% SiO₂

Rhyolite (Rhyolite (felsic volcanic rock)) — igneous

Rhyolite

Rhyolite (felsic volcanic rock)

Snowflake Obsidian (Volcanic glass containing Spherulite inclusions (primarily Cristobalite, SiO2)) — igneous

Snowflake Obsidian

Volcanic glass containing Spherulite inclusions (primarily Cristobalite, SiO2)

Mahogany Obsidian (Volcanic glass (high silica) with inclusions of Magnetite or Hematite) — igneous

Mahogany Obsidian

Volcanic glass (high silica) with inclusions of Magnetite or Hematite

Pumice (Pumice) — igneous

Pumice

Pumice

Black obsidian (Volcanic glass; predominantly silica-rich, noncrystalline SiO₂) — igneous

Black obsidian

Volcanic glass; predominantly silica-rich, noncrystalline SiO₂

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Tumbled mahogany obsidian (Obsidian, volcanic glass (composition typically rhyolitic)) — igneous

Tumbled mahogany obsidian

Obsidian, volcanic glass (composition typically rhyolitic)

Vesicular volcanic rock, likely pumice or scoriaceous basalt (Highly vesicular basaltic–andesitic volcanic rock; chiefly plagioclase, pyroxene, and volcanic glass) — igneous

Vesicular volcanic rock, likely pumice or scoriaceous basalt

Highly vesicular basaltic–andesitic volcanic rock; chiefly plagioclase, pyroxene, and volcanic glass

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

Snowflake Obsidian

Obsidian with Cristobalite inclusions (Amorphous SiO2 + SiO2 inclusions)

Pumice (Pumice (a highly vesicular volcanic glass)) — igneous

Pumice

Pumice (a highly vesicular volcanic glass)

Pumice (Vesicular volcanic glass (primarily SiO2)) — igneous

Pumice

Vesicular volcanic glass (primarily SiO2)

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

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

Obsidian

Obsidian (Volcanic Glass, primarily SiO2)

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

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Pumice (Vesicular Rhyolite (Amorphous glass)) — igneous

Pumice

Vesicular Rhyolite (Amorphous glass)

Obsidian with Cristobalite (Volcanic Glass (Amorphous Silicon Dioxide) with Cristobalite inclusions) — igneous

Obsidian with Cristobalite

Volcanic Glass (Amorphous Silicon Dioxide) with Cristobalite inclusions

Obsidian Arrowhead (Volcanic Glass (Amorphous Silicon Dioxide)) — igneous

Obsidian Arrowhead

Volcanic Glass (Amorphous Silicon Dioxide)

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Black obsidian (Volcanic glass (mostly rhyolitic silica glass; SiO₂-rich)) — igneous

Black obsidian

Volcanic glass (mostly rhyolitic silica glass; SiO₂-rich)

Polished black stone sphere, likely obsidian (Obsidian — naturally occurring volcanic glass, chiefly silica-rich rhyolitic glass) — igneous

Polished black stone sphere, likely obsidian

Obsidian — naturally occurring volcanic glass, chiefly silica-rich rhyolitic glass

Tumbled blue-gray stone, likely basalt (Basalt (fine-grained mafic volcanic rock; chiefly plagioclase and pyroxene, commonly with magnetite)) — igneous

Tumbled blue-gray stone, likely basalt

Basalt (fine-grained mafic volcanic rock; chiefly plagioclase and pyroxene, commonly with magnetite)

Likely black cabochon gemstone pendant (Uncertain; possibly black star sapphire, black spinel, or obsidian) — gemstone

Likely black cabochon gemstone pendant

Uncertain; possibly black star sapphire, black spinel, or obsidian

Black Obsidian (Volcanic Glass (Amorphous SiO2 with trace impurities)) — igneous

Black Obsidian

Volcanic Glass (Amorphous SiO2 with trace impurities)

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

Mahogany Obsidian

Obsidian (Volcanic Glass) with Hematite/Magnetite inclusions

Pumice (Pumicite) — igneous

Pumice

Pumicite

Pumice (Pumice (a highly vesicular volcanic glass)) — igneous

Pumice

Pumice (a highly vesicular volcanic glass)

Black Obsidian (Obsidian (Volcanic Glass, rich in SiO2)) — igneous

Black Obsidian

Obsidian (Volcanic Glass, rich in SiO2)

Obsidian with Slate/Tuff (Volcanic glass (SiO2) with associated pyroclastic rock) — igneous

Obsidian with Slate/Tuff

Volcanic glass (SiO2) with associated pyroclastic rock

Chalcedony (Common Opal or Agate variant) (Silicon Dioxide (SiO₂)) — mineral

Chalcedony (Common Opal or Agate variant)

Silicon Dioxide (SiO₂)

Black obsidian (Volcanic glass, predominantly rhyolitic silica glass (approximately 70–80% SiO₂)) — igneous

Black obsidian

Volcanic glass, predominantly rhyolitic silica glass (approximately 70–80% SiO₂)

Black Obsidian (Obsidian (Volcanic Glass, SiO2 + impurity)) — igneous

Black Obsidian

Obsidian (Volcanic Glass, SiO2 + impurity)

Pumice (Pumice (a highly vesicular volcanic glass)) — igneous

Pumice

Pumice (a highly vesicular volcanic glass)

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

Pumice

Pumice (a volcanic glass, primarily SiO2)

Obsidian (likely blue-sheen or coated obsidian) (Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, noncrystalline)) — igneous

Obsidian (likely blue-sheen or coated obsidian)

Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, noncrystalline)

Chalcedony (Grey/White Agate) (Silicon Dioxide (SiO₂)) — mineral

Chalcedony (Grey/White Agate)

Silicon Dioxide (SiO₂)