Sedimentary Rock (Specifically A Chemical Sedimentary Rock, Or A Chert If Considered Purely Mineral Aggregate)

Sandstone (likely Arkosic)

Clastic Sedimentary Rock (Sandstone)

Herkimer Diamond in Matrix

Quartz (SiO2) in Dolostone (CaMg(CO3)2)

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Carnelian (Red Agate)

Silicon dioxide (SiO2) with iron oxide impurities

Quartz (Druzy)

Silicon Dioxide (SiO2)

Blue Chalcedony

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Banded Agate

Agate (Cryptocrystalline Quartz, SiO2)

Pyrite in Shale

Iron Sulfide (FeS2)

Sandstone (likely Quartzose)

Arenite (primarily SiO2)

Banded Agate (Tumbled)

Agate (Variety of Chalcedony/Quartz), SiO2

Carnelian

Carnelian (SiO2 - Chalcedony colored by Iron Oxide)

Sandstone

Arenite (SiO2 based)

Druzy Quartz Geode (Vug)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Granite Gneiss

Gneiss (High-grade regional metamorphic rock)

Sandstone

Arenite (lithic or quartz sandstone)

Sandstone

Arenite (SiO2 principal component)

Sandstone (with Lichen)

Arenite (primarily SiO2)

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Jasper Agate (Carnelian Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions

Quartz Geode

Crystalline Silicon Dioxide (SiO2) in a Geode

Chert / Flint

Microcrystalline Quartz (SiO2)

Gneiss

Gneissic Metamorphic Rock

Sandstone

Sandstone (Silicon Dioxide, SiO2)

Sandstone

Arenite (typically composed of SiO2)

Sandstone

Arenite (primarily SiO2)

Sandstone

Arenite (primarily SiO2 with various cementing agents)

Sandstone (Calcareous Sandstone)

Calcareous Sandstone (primarily SiO2 with CaCO3 cement)

Red Sandstone

Arenite (with Iron Oxide)

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Granitic Gneiss

Gneiss (Metamorphic rock of granitic composition)

Chert (Flint nodule)

Silicon dioxide (SiO2)

Sandstone concretion (Ironstone-stained)

Arenite with Limonite/Hematite staining (Silica-based with Iron Oxides)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Sandstone Concretion

Ferruginous Sandstone Concretion

Jasper and Quartzite mix

Silicon Dioxide (SiO2) with impurities

Sandstone (Ferruginous Concretion)

Ferruginous Sandstone Concretion / SiO2 with Fe2O3 cement

Sandstone (with potential Arkose/Lithic characteristics)

Arenite (Sedimentary rock composed of sand-sized grains)

Limestone

Calcium Carbonate (CaCO3)

Quartz (Clear Quartz)

Silicon Dioxide (SiO2)