Man Made Object (Coin)

Quartzite

Quartzite (SiO2)

Quartzite (or Milky Quartz pebble)

Quartzite (Metamorphosed Sandstone) / Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Rough Quartz (likely Rose or Smoky variant)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Limestone (specifically Bituminous or Carbonaceous Limestone)

Calcium Carbonate (CaCO3) with Organic Impurities

Orange Calcite

Calcium Carbonate (CaCO3)

Clear Quartz

Quartz (Silicon Dioxide - SiO2)

Magnetite / Iron Ore

Magnetite (Fe3O4)

Chert (and Flint variant)

Chert (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Clear Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Sandstone (likely Arkosic)

Clastic Sedimentary Rock (primarily SiO2 with Feldspar)

Milky Quartz

Silicon Dioxide (SiO2)

Lepidolite

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

Blue Apatite

Chlorapatite / Fluorapatite (Ca5(PO4)3(F,Cl,OH))

Banded Iron Formation (BIF)

Banded Iron Formation (Magnetite-Hematite-Chert)

Quartz Vein in Metamorphic Rock

Silicon Dioxide (SiO2) within Metasedimentary host

Sandstone

Arenite (primarily SiO2)

Ironstone (with Limonite/Goethite)

Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O and Hematite Fe2O3)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

Quartzite

Quartzite (primarily SiO2)

Halite (Rock Salt)

Halite (Sodium Chloride, NaCl)

Quartz Pebble

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 oxides)

Sandstone (clastic)

Clastic Sedimentary Rock (primarily composed of SiO2)

Quartz (Quartzite Pebble)

Silicon Dioxide (SiO2)

Clear Quartz

SiO2 (Silicon Dioxide)

Sandstone

Arenite (composed primarily of SiO2)

Satin Spar (often marketed as Selenite)

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Sandstone (Fossiliferous)

Clastic Sedimentary Rock (primarily SiO2)

Quartzite Pebble

Recrystallized Quartz (SiO2)

Sandstone

Arenite (primarily SiO2)

Quartz Pebble (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Ferruginous Sandstone (with possible Epidote/Chlorite coloring)

Sandstone (SiO2 dominated with Fe2O3 staining)

Sandstone

Arenite

Quartzite pebble

Quartzite (SiO2)