Sedimentary Rock (Possibly Conglomerate Or Breccia With A Quartz Vein)

Banded Iron Formation (BIF) with Quartz

Banded Iron Formation, often composed of alternating layers of hematite (Fe2O3) or magnetite (Fe3O4) and chert (microcrystalline quartz, SiO2)

Ferruginous Sandstone (with ripple marks)

Arenite with Iron-Oxide (Fe2O3) cement

Geode (Chert or Quartz Nodule)

Silicon Dioxide (SiO2)

Gneiss (Metamorphic Rock)

Gneiss

Petrified Wood

Silicified wood (Quartz/Chalcedony - SiO2)

Quartz Crystal (specifically Rock Crystal)

Silicon Dioxide (SiO2)

Chert (White/Light Tan)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz (Milky/Common Quartz)

Silicon Dioxide (SiO2)

Chert (Chert Nodule with Cortex)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Agate

Agate (Microcrystalline Quartz, SiO2)

Quartz (Milky/Smoky variety)

Silicon Dioxide (SiO2)

Amethyst

Amethyst (Silica mineral, SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula: SiO2)

Gneiss (with Quartzite and Mica)

Gneiss

Sandstone Concretion

Clastic Sedimentary Rock (primarily SiO2 with mineral cement)

Mica Schist

Mica Schist (Composition typically contains Muscovite: KAl2(AlSi3O10)(OH)2 or Biotite: K(Mg,Fe)3AlSi3O10(OH)2 along with Quartz and Feldspar)

Milky Quartz (Ferruginous variety)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide cement)

Yellow Agate

Chalcedony (cryptocrystalline Quartz), SiO2

Sandstone (with Liesegang rings or joints)

Clastic Sedimentary Rock (primarily Quartz with Iron Oxide cement)

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Arsenopyrite in Quartz/Host Rock

Arsenopyrite (FeAsS)

Gold Nugget

Native Gold (Au)

Amethyst Lace Agate / Banded Amethyst

Silicon Dioxide (SiO2) with Fe3+ impurities

Jasper

Silicon dioxide (SiO2)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Red Moss Agate (Jasper)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Agatized Chert / Chalcedony

Silicon Dioxide (SiO2)

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Sandstone

Arenite (primarily SiO2 - Silicon Dioxide)

Amethyst (Druze)

Silicon Dioxide (SiO2) with iron impurities

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Gneiss

Gneiss (High-grade metamorphic rock)

Quartz Geode (partially formed)

Silicon Dioxide (SiO2)

Sandstone (Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Sandstone (Ferruginous)

Arenite (with Iron Oxide cement)

Ferruginous Sandstone (Iron-rich Sandstone)

Ferruginous Arenite