Sedimentary Rock (Technically A Microcrystalline Quartz Mineral Aggregate)

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Granite

Granite (silica-rich intrusive igneous rock)

Sandstone (Quartzite-rich)

Clastic Sedimentary Rock (primarily SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Sandstone (Quartz-rich)

Arenite (composed primarily of SiO2)

Sandstone (Ferruginous/Banded)

Clastic Terrigenous Sandstone (SiO2 with Fe2O3 cement)

Sandstone

Arenicola (comprising mostly Quartz, SiO2)

Garnet Schist or Garnet-bearing Quartzite

Metamorphic rock containing Almandine Garnet (Fe3Al2(SiO4)3) and Quartz (SiO2)

Sandstone (Quartzose)

Arenite (Siliciclastic sedimentary rock)

Sandstone with Foliose Lichen

Arenite (Rock matrix) with Xanthoparmelia or Flavoparmelia (Lichen genus)

Chert (often called Flint for dark variants)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (with potential mineral inclusions)

Clastic sedimentary rock (primarily Quartz, SiO2)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide mixture)

Limestone Breccia

Sedimentary Breccia (Calcareous)

Gneiss

High-grade metamorphic rock (Gneiss)

Limestone

Calcium Carbonate (CaCO3)

Granite

Granite (phaneritic intrusive igneous rock consisting of quartz, feldspar, and mica)

Green Quartzite (Aventurine variety)

Silicon Dioxide (SiO2) with inclusions of Fuchsite

Amygdaloidal Basalt with Quartz/Calcite Inclusions

Amygdaloidal Basalt (SiO2 / CaCO3 inclusions)

Limonite Concretion (Ironstone)

Limonite (FeO(OH)·nH2O) / Goethite

Green Aventurine (Green Quartzite)

Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)

Sandstone (with Limonite staining)

Arenite (primarily SiO2 with FeO(OH)·nH2O)

Quartzite Pebble (with Iron Staining)

Quartzite (SiO2)

Chert / Flint

Chert (varietal name for microcrystalline quartz). Chemical formula: SiO₂

Banded Agate

Agate (Cryptocrystalline variety of Quartz, SiO2)

River/Stream Pebble

Clast / Detrital Grain / Rounded Sedimentary Particle (Compositionally variable, commonly Quartz, Feldspar, Chert, or other resistant rock fragments)

Granite Cobble

Plutonic Igneous Rock (Granitic)

Quartz with Chalcedony

Silicon dioxide (SiO2)

Sandstone

Arenite (composed primarily of SiO2)

Agate

Silicon Dioxide / Cryptocrystalline Quartz (SiO2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Clear Quartz (or Rock Crystal)

Quartz (SiO₂ - Silicon Dioxide)

Bumblebee Jasper

Calcite with Arsenic and Manganese oxides (technically a volcanic rock)

Quartz Druze on Matrix (Geode Fragment)

Quartz (Silicon Dioxide, SiO2)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Red Sandstone

Sandstone (principally Quartz with Iron Oxide coating)

Granite

Phaneritic Plutonic Felsic Rock (K-Feldspar + Quartz + Plagioclase)

Chalcedony Geode Fragment

Microcrystalline Quartz (SiO2)

Granite

Phaneritic Felsic Igneous Rock

Quartz (Milky or Cloudy Quartz)

Silicon Dioxide (SiO2)

Gneiss

Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)

Dragon Vein Agate

Chalcedony (Quartz) - SiO2