Sedimentary Rock (Specifically A Concretion Or Possibly A Geode)

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone (likely Quartz Sandstone)

Arenite (SiO2 based)

Sandstone

Arenite (composed primarily of SiO2)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone

Arenite (SiO2 based)

Sandstone (Quartz Arenite)

Sandstone (dominated by SiO2 quartz grains)

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 staining)

Chert (specifically a stream-worn Chert Nodule)

Sedimentary Cryptocrystalline Quartz (SiO2)

Sandstone

Arenite (mostly SiO2)

Sandstone (Ferruginous)

Arenite (Fe2O3 rich)

Sandstone (clastic)

Clastic Sedimentary Rock (primarily composed of SiO2)

Basalt Pebble

Basalt (Aphanitic Mafic Volcanic Rock)

Basalt with Olivine Phenocrysts

Porphyritic Basalt (Mineral formula of Olivine: (Mg,Fe)2SiO4)

Banded Calcite or Travertine

Calcium Carbonate (CaCO3)

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Sandstone Pebbles

Arenite (Sedimentary rock composed of sand-sized grains)

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Limestone

Calcium Carbonate (CaCO3)

Limestone

Calcium Carbonate (CaCO3)

Limestone (with potential fossil inclusions)

Calcium Carbonate (CaCO3)

Sandstone (likely Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Pumice

Felsic Volcanic Glass / Vesicular Rhyolite

Basalt with Quartz/Calcite Veins

Basalt (Aphanitic Mafic Volcanic Rock) with Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3) inclusions

Travertine

Terrestrial Sedimentary Rock (Calcium Carbonate, CaCO3)

Sandstone

Arenite (primarily SiO2)

Pumice

Vesicular Rhyolite or Dacite

Sandstone (with Iron Staining)

Clastic sedimentary rock (SiO2 with Fe2O3 impurities)

Quartz (specifically Milky/White Quartz)

Silicon Dioxide (SiO2)

Asphalt (Bituminous pavement)

Bituminous concrete / Asphalt

Chert (specifically Red Chert/Jasper variety)

Silicon Dioxide (SiO2)

Chert (specifically Red Chert/Jasper nodule)

Microcrystalline Quartz (SiO2)

Banded Agate (specifically Lake Superior Agate or similar)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Chert (specifically a variety like Flint or River Jasper with Iron Oxidation)

Microcrystalline Quartz (SiO2)

Chert (specifically River Stone / Jasper variety)

Microcrystalline Quartz (SiO2)

Sandstone (Quartzite-rich)

Clastic sedimentary rock (primarily SiO2)

Sandstone (likely Graywacke or Arkose variant)

Clastic Sedimentary Rock (SiO2 based)

Sandstone (likely Greywacke variant)

Arenite

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone (Calcareous or Ferruginous)

Clastic sedimentary rock (SiO2 with CaCO3 or Fe2O3 cement)

Quartz

Silicon Dioxide (SiO₂)