Tektite (Natural Glass)

Smooth river pebble

Indeterminate lithology; likely fine-grained quartz-rich sandstone, siltstone, or weathered chert

Smoky Quartz

Silicon Dioxide (SiO2)

Sandstone

Sandstone (clastic sedimentary rock composite)

Sandstone

Arenite (primarily SiO2)

Sandstone (likely Quartzose Sandstone)

Clastic Sedimentary Rock (primarily SiO2)

Quartz (Citrine variety)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite

Sandstone

Arenite (primarily SiO2)

Slag Glass

Anthropogenic Amorphous Silicon Dioxide

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)

Chert (Siliceous Pebble)

Microcrystalline / Cryptocrystalline Quartz (SiO2)

Amethyst

Silicon Dioxide with iron impurities (SiO2)

Orange Calcite / Quartzite with Iron Staining

Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3) with Iron Oxide impurities

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Granite

Phaneritic Felsic Igneous Rock

Clear Quartz

Silicon Dioxide (SiO2)

Quartz (Citrine variety)

Silicon Dioxide (SiO2)

Amethyst

Silicon Dioxide (SiO2)

Sandstone (Quartzose type)

Arenite (primarily SiO2)

Quartz (Smoky/Milky Variety)

Silicon Dioxide (SiO2)

Smoky Quartz

Crystalline Silicon Dioxide (SiO2)

Slag (Industrial Byproduct)

Ferrous/Non-ferrous Silicate

Clear quartz crystal sphere

Quartz (silicon dioxide, SiO₂)

Smoky Quartz

Smoky Quartz (Silicon Dioxide - SiO2)

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Carved quartz skull, likely smoky quartz or gray chalcedony

Silicon dioxide (SiO₂), quartz or microcrystalline quartz

Obsidian (likely blue-sheen or coated obsidian)

Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, noncrystalline)

Citrine Quartz / Iron-stained Quartz

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon dioxide (SiO2)

Citrine Quartz

Silicon Dioxide (SiO2)

Citrine

Citrine (Silicon Dioxide - SiO2)

Red Cubic Zirconia (Simulated Garnet)

Zirconium Dioxide (ZrO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Green aventurine beads

Quartz (SiO₂), typically green quartzite/aventurine with fuchsite mica inclusions

Sandstone

Clastic Sedimentary Rock (composed mostly of quartz, SiO2)

Blue-beaded gemstone jewelry, likely lapis lazuli or dyed blue agate

Uncertain from the image; possible lazurite-bearing lapis lazuli (Na₃Ca(Si₃Al₃)O₁₂S) or blue chalcedony (SiO₂)

Green Aventurine

Silicon Dioxide with Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Green Aventurine

Aventurine Quartz (SiO2 with inclusions of Fuchsite)

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2 + K(Al,Cr)2AlSi3O10(OH)2