Obsidian
Volcanic Glass (70-75% SiO2)
Category
Browse non geological specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (70-75% SiO2)
Opalite
Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)
Quartz-veined Siltstone/Greywacke
Clastic Sedimentary Rock with Quartz Infill (SiO2 vein)
Green Common Opal
Hydrated Silica (SiO2·nH2O)
Obsidian
Volcanic Glass (predominantly SiO2)
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2 + Fe2O3)
Anthracite Coal
Anthracite (Carbon based fossil fuel)
Shale or Argillite
Shale (fine-grained clastic sedimentary rock) or Argillite (low-grade metamorphic rock derived from shale)
Gold
Aurum (Elemental Gold, Au)
Rose Quartz
Rose Quartz (SiO2)
Cobalt Glass Slug (Man-made Glass)
Amorphous Silica with Cobalt Oxide (SiO2 + CoO)
Anthracite Coal
Anthracite (Carbon-rich mineraloid)
Slag (Industrial Glass Slag)
Amorphous Silicate Glass (often containing Al, Ca, Mg, and Ti oxides)
Obsidian (Apache Tear)
Obsidian / Amorphous Volcanic Glass (main component: SiO2)
Libyan Desert Glass
Tektite (high-silica impact glass), SiO2
Sea Glass (Teal/Turquoise)
Amorphous Silica (SiO2) with trace metal oxides
Mahogany Obsidian Arrowhead
Obsidian (volcanic glass) with Hematite inclusions
Quartzite Pebbler
Quartzite (primarily SiO2)
Sea Glass (often mistaken for Gemstones)
Amorphous Silica (SiO2) with trace additives
Quartzite pebble
Quartzite (SiO2 dominated)
Anthracite Coal
Anthracite (Carbon-based sedimentary-metamorphic rock)
Quartzite with inclusions
Metamorphic Rock (Mainly SiO2)
Quartzite Cobble
Quartzite (primarily SiO2)
Obsidian
Volcanic Glass (SiO2)
Obsidian (Gold Sheen)
Obsidian (SiO2 + impurities)
Pink Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Chert (River Cobble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Green Glass Slag
Amorphous Silicon Dioxide (SiO2) with metal oxide impurities
Quartzite (Ferruginous)
Metamorphosed Quartz Sandstone (SiO2 with Fe2O3 inclusions)
Obsidian
Obsidian (Amorphous volcanic glass, predominantly SiO2)
Quartzite
Quartzite (primarily SiO2)
Amber
Succinite (a specific high-quality amber from the Baltic)
Quartzite
Quartzite (SiO2)
Quartzite Pebble
Quartzite (primarily SiO2)
River Stone (Quartzite)
Metamorphosed Sandstone (SiO2)
Obsidian
Obsidian (principally SiO2, 70% or more silica)
Limonite (Iron Ore/Hydrated Iron Oxide)
Limonite (mixture of FeO(OH)·nH₂O minerals, mainly Goethite, FeO(OH) and Lepidocrocite, FeO(OH))
Rough Dark Green Sapphire
Corundum (Al2O3)
Amber
Succinite (approximate formula C10H16O)
Quartzite (with Iron Staining)
Metamorphosed Quartz Sandstone (SiO2)
Quartzite pebble
Quartzite (SiO2)
Quartzite
Quartzite (primarily SiO2)