Sedimentary Rock (Cryptocrystalline Quartz)

Shale or Siltstone

Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)

Granodiorite or Diorite

Granodiorite / Diorite

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Sandstone (with Liesegang rings or Oxidation)

Arenite (primarily Quartz SiO2 with Iron Oxide Fe2O3 staining)

Chert (varietal known as Jasper or Flint)

Silicon Dioxide (SiO2)

Ferruginous Sandstone (Gritstone)

Clastic sedimentary rock with iron-rich cement (FeO(OH)·nH2O)

Quartz with Iron Staining

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)

Botryoidal Quartz / Calcite Geode crust

Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)

Chalcedony (Agate/Chert variety)

Silicon Dioxide (SiO2)

Quartz Pebble (Iron-stained)

Silicon Dioxide (SiO2)

Sandstone (likely Graywacke or Lithic Sandstone)

Arenite / Wacke (SiO2 based with lithic fragments)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Granite Gneiss

Gneiss (High-grade regional metamorphic rock)

Gneiss (specifically a Granitic Gneiss)

Gneiss (typically composed of Quartz, Feldspar, and Mica/Amphiboles)

Jasper (Iron-stained Quartz)

Silicon Dioxide (SiO2) with iron oxide inclusions

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Graywacke (River Cobble)

Graywacke (Lithic Sandstone)

Quartzite

Quartzite (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Quartzite

Quartzite (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)

Red Jasper

Opaque microcrystalline Quartz (SiO2 with Fe2O3 inclusions)

Chalcedony

Chalcedony (a microcrystalline variety of Quartz, SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz (Milky or Smoky variety)

Silicon Dioxide (SiO2)

Gneiss

Gneiss (quartz-feldspar-biotite gneiss)

Greenschist (containing Epidote and Quartz)

Greenschist (Epidote-Chlorite-Actinolite Schist)

Red Sandstone

Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)

Schist (Micaceous Schist)

Schist (containing mainly Muscovite and Quartz)

Basalt with Quartz Vein

Mafic Igneous Rock (SiO2 filling)

Shale

Fissile Mudstone (primarily composed of clay minerals and quartz grains)

Red Jasper

Jasper (Silicon Dioxide based crypto-crystalline Quartz with Iron inclusions)

Shale (sub-type: Carbonaceous Shale)

Lutaceous Sedimentary Rock

Red Tiger's Eye beads

Tiger's Eye (variety of Chalcedony, SiO2)