Milky Quartz
Silicon Dioxide (SiO2)
Category
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
Milky Quartz
Silicon Dioxide (SiO2)
Basalt (River Stone)
Basalt
Basalt
Mafic volcanic rock (various silicate minerals)
K-Feldspar / Granite Pegmatite
Potassium Feldspar (Microcline/Orthoclase) with Quartz
Snowflake Obsidian
Volcanic Glass with Spherulitic Cristobalite (SiO2)
Quartz Geode
Silicon Dioxide (SiO2) within a sedimentary or igneous host
Vuggy Quartz on Matrix
Silicon Dioxide (SiO2)
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (mostly SiO2)
Chalcedony (Yellow Agate / Carnelian Chalcedony)
Silicon Dioxide (SiO2)
Diorite (River Cobble)
Phaneritic Intermediate Plutonic Rock
Diorite
Diorite (Intermediate Plutonic Rock)
Diorite
Phaneritic intermediate plutonic rock
Diorite (Spotted or Dalmatian Stone effect)
Diorite (Intermediate Plutonic Rock)
Basalt (with Plagioclase Phenocrysts)
Porphyritic Basalt
Copper-bearing Basalt with Epidote and Quartz
Native copper in basalt amygdaloidal matrix
Porphyry
Porphyritic Basalt or Porphyritic Andesite
Basalt with Quartz Veins
Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene) with SiO2 inclusions
Quartz
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Scoria (with likely iron oxidation)
Scoria (Basaltic Scoria)
Basalt with Scoria/Vesicular Texture
Extrusive Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Porphyritic Basalt
Porphyritic Aphanitic Basalt with Plagioclase Phenocrysts
Vesicular Basalt (Scoria)
Scoriaceous Basalt (FeMgSiO3-rich)
Pumice
Pumice (Volcanic Glass Foam)
Vesicular Basalt
Basalt
Basalt River Stone
Basalt
Milky Quartz
Quartz (Silica / Silicon Dioxide), SiO2
Porphyritic Basalt
Porphyritic Basalt (Mafic extrusive rock)
Obsidian Arrowhead
Volcanic Glass (predominantly SiO2)
Basalt
Basalt
Granodiorite
Granodiorite (Na,Ca)(Si,Al)4O8
Basalt
Basalt (High-iron/magnesium silicate rock)
Apache Tears (Tumbled Obsidian)
Volcanic Glass (SiO2 + impurities)
Scoria (Lava Rock)
Vesicular Basalt / Scoria
Scoria
Vesicular Basalt / Scoria (Mafic volcanic rock)
Black Obsidian
Volcanic Glass (SiO2 with impurities)
Obsidian Arrowhead Replica (or similar knapped stone)
Obsidian (volcanic glass) or Chert
Obsidian
Volcanic Glass (SiO2 + impurities)
Gold Sheen Obsidian
Volcanic Glass (SiO2 with inclusions)
Obsidian
Volcanic Glass (SiO2 + impurities)
Obsidian
Volcanic Glass (mostly SiO2)
Black Obsidian
Volcanic Glass (SiO2 + impurities)