Obsidian
Obsidian (Volcanic Glass, SiO2)
Category
Browse non geological specimens identified by the Rock Identifier community.
Obsidian
Obsidian (Volcanic Glass, SiO2)
Conglomerate
Conglomerate (SiO2, Al2O3, Fe2O3, CaCo3)
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Obsidian
Volcanic Glass (SiO2)
Quartzite
Quartzite (primarily SiO2)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Slag
Ferrous Slag (Amorphous calcium-magnesium-aluminum silicates)
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Amber
Succinite (Carbon-based organic compound; approximate formula C10H16O)
Quartzite
Quartzite (composed primarily of SiO2)
Quartzite
Quartzite (Primary mineral: Silicon Dioxide, SiO₂)
Mahogany Obsidian
Obsidian (SiO2 + Fe2O3)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Quartzite
Quartzite (primarily SiO2)
Snowflake Obsidian
Obsidian with Cristobalite inclusions (70–75% SiO2)
Quartzite
Quartzite (primarily SiO2)
Obsidian
Obsidian (volcanic glass; primarily SiO2)
Obsidian
Obsidian (Extrusive Volcanic Glass)
Obsidian
Obsidian (volcanic glass), amorphous SiO2 + impurities
Obsidian
Volcanic glass (mainly SiO2)
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Obsidian (Black Obsidian)
Obsidian (Volcanic Glass)
Quartzite
Quartzite (SiO2)
Grey Quartzite Pebble
Quartzite (primarily SiO2 - Silicon Dioxide)
Goldstone (Red/Brown)
Aventurine Glass (SiO2 with Copper inclusions)
Siltstone
Siltstone
Obsidian
Obsidian (Volcanic Glass)
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Slag Glass (Cullet Glass)
Amorphous Silica (Industrial byproduct)
Common Opal (Green Opal / Pistachio Opal)
Hydrated silica (SiO2·nH2O)
Obsidian
Volcanic Glass (SiO2 rich)
Conglomerate
Conglomerate (Sedimentary Clastic Rock)
Obsidian
Volcanic Glass (predominantly SiO2 – Silicon Dioxide, but non-crystalline)
Obsidian (worked into an arrowhead profile)
Obsidian (volcanic glass), primarily SiO2 (Silicon Dioxide)
Graphite
Graphite (Carbon, C)
Wonderstone (Liesegang Sandstone)
Silicified Sandstone with Liesegang Rings (SiO2 + FeO(OH))
Obsidian (specifically Mahogany Obsidian)
Volcanic glass (high silica content, SiO2)
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Obsidian (principally SiO2 + MgO, Fe3O4)
Obsidian
Volcanic Glass (Primary component: SiO2)