Pumice (with oxidation)
Pumice (Vitreous pyroclastic rock)
igneous
Category
Igneous Rock (Volcanic Glass)
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
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Obsidian with Slate/Tuff
Volcanic glass (SiO2) with associated pyroclastic rock
igneous
Vesicular volcanic rock, likely pumice or scoriaceous rhyolite
Silica-rich vesicular volcanic rock; commonly rhyolitic pumice (SiO₂-rich glass)
igneous
Obsidian
Volcanic glass (mainly SiO2)
Igneous
Quartz on Basalt
Silicon Dioxide (SiO2) on Mafic Igneous Rock
Mineral on Igneous Rock
Pumice
Pumice (Volcanic silicate glass)
igneous
Pumice
Pumice (a vesicular volcanic glass)
igneous
Pumice or vesicular volcanic tuff
Pumice: highly vesicular volcanic glass, chiefly rhyolitic to dacitic; possible tuff: lithified ash and pumice fragments
igneous
Polished snowflake obsidian
Obsidian, volcanic glass (SiO₂-rich rhyolitic composition) with cristobalite spherulites
igneous
Pumice
Pumice (a highly vesicular volcanic glass)
igneous
Snowflake Obsidian
Obsidian with Spherulitic Cristobalite (SiO2)
igneous
Pumice
Pumice (Amorphous volcanic glass)
igneous
Pumice
Pumice (Amorphous volcanic glass)
igneous
Pumice
Pumicite (Amorphous Volcanic Glass)
igneous
Pumice
Pumicite (Amorphous Volcanic Glass)
igneous
Obsidian
Amorphous volcanic glass (primarily SiO2)
igneous
Pumice
Pumice (a volcanic glass, primarily SiO2 with Al2O3)
igneous
Likely weathered basalt or andesite fragment
Fine-grained mafic to intermediate volcanic rock; commonly plagioclase ± pyroxene ± olivine
igneous
Pumice
Pumice (Volcanic glass / Felsic igneous rock)
igneous
Pumice
Pumice (Vesicular volcanic glass / Rhyolite or Trachyte)
igneous
Agate (Carnelian Agate with Quartz Matrix)
Silicon Dioxide (SiO2)
mineral
Pumice
Pumice (Vesicular Felsic Igneous Rock)
igneous
Polished black pebble, likely basalt
Basalt; predominantly plagioclase feldspar, pyroxene, and commonly olivine or magnetite
igneous
Snowflake Obsidian
Obsidian with Cristobalite inclusions (70–75% SiO2)
igneous
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Pumice
Pumice (Vesicular Felsic Glass)
igneous
Pumice
Pumice (a highly vesicular volcanic glass)
igneous
Scoria
Scoria (Extrusive Volcanic Rock)
igneous
Pumice
Pumice (Silicic volcanic glass)
igneous
Pumice
Pumice (a highly vesicular volcanic glass)
igneous
Weathered conglomeratic volcanic rock
Likely basaltic volcanic breccia or agglomerate, with plagioclase, pyroxene, volcanic glass, and lithic fragments
igneous
Rounded river cobble, likely basalt or weathered andesite
Fine-grained mafic volcanic rock; likely basalt (plagioclase ± pyroxene/olivine)
igneous
Polished black stone, likely basalt or black jasper
Indeterminate; possible fine-grained basalt (plagioclase–pyroxene) or black jasper/microcrystalline quartz
igneous
Chalcedony (Agate/Quartz)
Silicon Dioxide (SiO2)
mineral
Basalt with Plagioclase or Quartz Inclusion
Melanocratic Basalt with Porphyritic Inclusion
igneous
Basalt with vesicles/amygdules
Basalt (containing volcanic glass and plagioclase)
igneous
Vesicular Basalt (Scoria)
Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
igneous
Weathered vesicular volcanic rock, likely basaltic scoria
Vesicular basalt/scoria; chiefly plagioclase, pyroxene, olivine, and volcanic glass
igneous
Obsidian
Volcanic Glass (Amorphous Silica)
igneous
Pumice
Pumicite
igneous
Granite and Pumice
Granite (plutonic rock) and Pumice (volcanic glass)
igneous
Quartz geode or quartz-bearing rock
Quartz (SiO₂), likely in a chalcedony- or basalt-hosted cavity
mineral