Obsidian
Volcanic Glass (SiO2)
Category
Browse igneous specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (SiO2)
Basalt Beach Pebble
Basalt (Aphanitic Mafic Volcanic Rock)
Vesicular Basalt with Secondary Mineral Infill
Mafic Volcanic Rock (Basalt)
Basalt with Weathered Surface
Basalt
Granite
Granite
Granodiorite
Phaneritic Granodiorite
Pumice
Pumice (Volcanic glass with vesicular texture)
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock with secondary mineral fillings)
Basalt Pebble
Basalt (Mafic Volcanic Rock)
Apache Tear (Obsidian)
Volcanic glass (SiO2 - Silicon Dioxide)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)
Pink Granite
Phaneritic Plutonic Felsic Rock (Granite)
Pumice (Volcanic Rock)
Vesicular volcanic rock (composed largely of amorphous volcanic glass)
Obsidian
Volcanic Glass (70% or more SiO2)
Granodiorite (Gneissic texture)
Granodiorite (containing Quartz SiO2, Plagioclase Feldspar, and Biotite)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Granite
Granite (Felsic Plutonic Rock)
Obsidian
Obsidian (Volcanic Glass)
Epidote in Basalt
Epidotized Basalt (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH) in Mafic Igneous Host)
Snowflake Obsidian
Obsidian with Cristobalite inclusions
Granite
Phaneritic plutonic rock (Quartz, Feldspar, Mica)
Diorite
Diorite
Granite
Granite (Mainly Quartz: SiO2, Feldspar: KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8, and Mica)
Decomposed Granite
Grano-diorite/Granite-residuum (SiO2 primary)
Pegmatite containing Muscovite and Quartz
Granitic Pegmatite (SiO2 with KAl2(AlSi3O10)(OH)2)
Granitic Pegmatite
Granitic Pegmatite (primarily SiO2 with KAlSi3O8)
Granite Cobble
Granite (Phaneritic Quartz-Feldspar specimen)
Apache Tears (Obsidian)
Volcanic Glass (SiO2 - Silicon Dioxide with impurities)
Granite
Granite (Felsic Plutonic Rock)
Granodiorite
Granodiorite (Na,Ca)(Si,Al)4O8
Granite
Granite (Felsic Plutonic Rock)
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Basalt River Stone
Basalt (Mafic volcanic rock, primarily Plagioclase and Pyroxene)
Basalt (with Brass Inlay)
Basalt (Mafic volcanic rock)
Basalt
Basalt (Mafic volcanic rock)
Granitic Gravel
Granite (Quartz, Feldspar, and Mica mixture)
Ferrocoke or Slag
Anthropogenic pyrometallurgical residue
Sheen Obsidian
Volcanic glass (SiO2 with inclusions)
Granite Cobble
Phaneritic Felsic Intrusive Rock (Granite)
Granite
Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)
Pumice
Pumicite
Black Obsidian
Obsidian (Amorphous volcanic glass, SiO2)