Anthropogenic (Man Made Artifact)

Shale

Shale (composition varies: primarily clay minerals and quartz)

Quartzite

Quartzite (mostly SiO2)

Quartz pebble

Silicon Dioxide (SiO2)

Milky Quartz (Stained with Iron)

Silicon Dioxide (SiO2)

Fossiliferous Limestone (Coquina / Shell Limestone)

CaCO3 (Calcium Carbonate)

Quartzite Pebble

Quartzite (primarily SiO2)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Pink Halite (Himalayan Salt)

Halite (Sodium Chloride, NaCl)

Sandstone

Arenite (SiO2 primarily)

Bull Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Orthoclase Feldspar

KAlSi3O8 (Potassium Aluminum Silicate)

Quartzite Pebble

Quartzite (primarily SiO2)

Arfvedsonite in Quartz (also known as Eudialyte/Garnet Syenite variety)

Arfvedsonite [Na3(Fe2+)4Fe3+Si8O22(OH)2] within a silicate matrix

Kyanite

Kyanite (Al2SiO5)

Quartzite

Quartzite (principally SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Sandstone

Arenite (composed primarily of SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide cement)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz (Drusy/Crystalline)

Silicon Dioxide (SiO2)

Quartzite Pebble

Metamorphic Quartzite (SiO2)

Sandstone (Quartzite Pebble)

Arenite (primarily SiO2)

Celestine (or Celestite) on Matrix

Celestine (SrSO4)

Milky Quartz

Silicon Dioxide (SiO2)

Limonite (Iron Ore)

Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)

River Quartz Cobble

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Shale

Shale (comprised mostly of clay minerals and quartz)

Milky Quartz

Silicon Dioxide (SiO2)

White Quartz (Carved or Tumbled)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (with iron oxide cement, Fe2O3)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartzite Pebble

Quartzite (SiO2)

Olivine in Basalt (Peridotite Xenolith)

Forsterite-rich Olivine (Mg2SiO4) in Aphanitic Basalt

Milky Quartz

Silicon Dioxide (SiO2)

Quartz (with Iron staining)

Silicon Dioxide (SiO2)

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Quartzite with Iron Inclusions

Metamorphosed Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)