Manufactured Glass (Simulant)

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Quartzite River Rock

Quartzite (SiO2)

Sandstone

Arenite (primarily SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Red Sandstone

Arenite (Ferruginous Sandstone)

Sandstone

Arenite (primarily SiO2)

Sandstone (Quartzite-rich)

Clastic sedimentary rock (primarily SiO2)

Sandstone

Arenite (primarily SiO2)

Quartz pebble

Silicon Dioxide (SiO2)

Sandstone (likely Quartz Sandstone)

Arenite (composed primarily of SiO2)

Quartz Pebble (Citrine or Iron-Stained)

Silicon Dioxide (SiO2)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Quartz

Silicon Dioxide (SiO2)

Sandstone (likely Fossiliferous)

Arenite / Fossiliferous Sandstone (SiO2 composition)

Sandstone

Arenite (Siliclastic sedimentary rock)

Sand Grain (Silica/Quartz Grain)

Silicon Dioxide (SiO2)

Faceted citrine-colored gemstone (likely synthetic/display stone)

Quartz, SiO₂, if natural citrine; possibly synthetic sapphire or glass imitation

Slag Glass

SiO2 (Silicon Dioxide) with impurities

Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite (Clastic Sedimentary Rock)

Clear Quartz

Silicon Dioxide (SiO2)

Slag (Industrial Glass Slag)

Amorphous Silica / Ferro-silicate Slag

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial Man-made)

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)

Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)

Clear Quartz

Silicon Dioxide (SiO2)

Dark rounded stone, possibly basalt

Likely fine-grained basalt; exact identification is uncertain from the photograph

Quartz

Silicon Dioxide (SiO2)

Quartz (Pale Rose or Milky Variety)

Silicon Dioxide (SiO2)

Quartzite Pebble

Metamorphic rock predominantly composed of Quartz (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Blue Slag Glass

Man-made Silicon Dioxide (Amorphous)

Slag Glass (Cullet Glass)

Amorphous Silica (Industrial byproduct)

Clear Quartz

Silicon Dioxide (SiO2)

Opalite

Synthetic Silicon Dioxide (SiO2)

Amber (possibly a small polished amber cabochon)

Fossilized tree resin; amber is an organic gemstone, not a mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Smoky Quartz with Feldspar

Silicon Dioxide (SiO2) with Potassium Feldspar (KAlSi3O8)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)