Not A Geological Specimen

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Chrysocolla

Hydrated copper phyllosilicate mineral (Cu,Al)2H2Si2O5(OH)4·n(H2O)

Banded Sandstone (Liesegang Rings)

Sedimentary sandstone with Iron oxide precipitates

Desert Rose

Gypsum (CaSO4·2H2O) or Barite (BaSO4) with Sand inclusions

Chert (Chert / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Amygdaloidal Basalt

Amygdaloidal Basalt

Magnetite (potentially Hematite-rich)

Magnetite (Fe3O4)

Quartzite Pebble (with Iron Staining)

Quartzite (SiO2)

Quartz (Clear/White)

Silicon Dioxide (SiO2)

Petrified Wood (Silicified Wood)

Silicified Wood / Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Pyrite

Iron Disulfide (FeS2)

Quartz (Common or Milky Quartz)

Silicon Dioxide (SiO2)

Sandstone (Quartz-rich)

Sandstone (SiO2 dominated)

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Obsidian

Volcanic Glass (predominantly SiO2)

Quartz (Chert/Chalcedony Variety)

Silicon Dioxide (SiO2)

Obsidian

Volcanic Glass (Amorphous Silicon Dioxide , SiO2)

Basalt

Extrusive mafic rock (Basalt)

Quartz (likely a weathered/tumbled piece)

Quartz (SiO₂)

Honey Calcite Geode Segment

Calcite (Calcium Carbonate, CaCO3)

Milky Quartz

Silicon Dioxide (SiO2)

Rhyolite

Rhyolite (High-silica volcanic rock)

Quartz (Common or Milky)

Silicon Dioxide (SiO2)

Quartz (Milky Quartz Pebbles)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Siltstone with Quartz Vein

Siltstone (primarily SiO2, Al2O3, Fe2O3)

Basalt with Calcite Veins

Basalt (Mafic Volcanic Rock)

Limonite after Pyrite (Pseudomorph)

FeO(OH)·nH2O following FeS2

Clear Quartz

Silicon Dioxide (SiO2)

Clear Quartz Crystal

Silicon Dioxide (SiO2)

Quartz with Mica Schist (Pegmatite Specimen)

SiO2 (Silicon Dioxide) and Phyllosilicates (Biotite/Muscovite)

Sandstone (Quartzose Sandstone)

Clastic Sedimentary Rock (Lithic arenite / Quartz arenite)

Red Quartzite / Ferruginous Sandstone

Quartzite (SiO2 with iron oxide impurities)

Petrified Wood

Silicified Wood (primarily SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Milky Quartz

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Jasper (specifically Yellow/Red Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions

Chert / Flint

Cryptocrystalline Quartz (Silicon Dioxide, SiO2)

Quartzite (Quartz-rich Cobble)

Quartzite (SiO2)