Manufactured Glass

Sandstone

Clastic Sedimentary Rock (composed mostly of quartz, SiO2)

Sandstone

Arenite (SiO2 principal)

Sandstone (Beach Pebble)

Clastic sedimentary rock (primarily Quartz and Feldspar)

Milky Quartz with Mineral Inclusions

Silicon Dioxide (SiO2) with miscellaneous inclusions

Sandstone (likely Quartzose)

Arenite (SiO2 principal mineral)

Feldspar (Orthoclase)

Orthoclase Feldspar (KAlSi3O8)

Sandstone (likely with Quartz Veining)

Arenite (primarily SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz (Pale Rose or Milky Variety)

Silicon Dioxide (SiO2)

Green Slag Glass

Amorphous Silica / Glassy Blast Furnace Slag

Quartz Pebble (often referred to as 'Sea Glass' or 'River Stone' when worn smooth)

Silicon Dioxide (SiO2)

Chert

Microcrystalline Quartz (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Red Slag Glass

Amorphous Silica (Industrial byproduct with metallic oxide dopants)

Quartz Pebble (Milky Quartz)

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2, often with CaCO3 or Fe2O3 cement)

Quartzite pebble

Quartzite (primarily SiO2)

Sandstone (with biological crust)

Arenite (SiO2 based)

Quartz Pebble

Silicon Dioxide (SiO2)

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (Fe2O3 enriched)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Sandstone or Limestone

Arenite or Calcareous Sedimentary Rock

Clear Quartz

Silicon Dioxide (SiO2)

Rough Quartz (likely Rose or Smoky variant)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartzite pebble

Quartzite (SiO2)

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Quartz (Milky/Gray variety)

Silicon Dioxide (SiO2)

Quartz Crystal Point

Silicon Dioxide (SiO2)

Quartz (with iron oxide staining)

Silicon Dioxide (SiO2)

Pink Feldspar

Orthoclase Feldspar (KAlSi3O8)

Quartz

Silicon Dioxide (SiO2)

Sandstone (likely Arkose or Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Clear Quartz

Silicon dioxide (SiO2)

Cloudy Quartz

Silicon Dioxide (SiO2)

Quartz (specifically Clear Quartz or Rock Crystal)

Silicon Dioxide (SiO2)

River Quartz Cobble

Silicon Dioxide (SiO2)

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Ferrous Slag

Fused calcium-iron silicates (Industrial Slag)