Sedimentary Rock (Specifically A Clastic Sedimentary Rock Formed Into A Cobble)

Sandstone or Siltstone

Arenite (if sandstone)

Sandstone (Red Flagstone)

Clastic sedimentary rock (primarily Quartz - SiO2)

Jasper Conglomerate (Puddingstone)

Jasper Conglomerate (Siliceous Sedimentary Rock)

Ferruginous Sandstone

Sandstone (rich in iron oxides/hydroxides)

Sandstone

Arenite (primarily SiO2 with iron oxide cementation)

Sandstone with Liesegang Rings

Arenite with secondary Iron oxide (Limonite/Goethite) precipitation

Sandstone (Ferruginous)

Arenite (Fe-rich)

Sandstone (Micaceous/Feldspathic variant)

Arenite (specifically subarkose or lithic arenite)

Conglomerate

Conglomerate (a clastic sedimentary rock)

Chert (Agatized/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Conglomerate

Conglomerate (Rock composed predominantly of rounded clasts > 2mm)

Sandstone

Clastic sedimentary rock (primarily SiO2)

River Cobble (Quartzite-rich Sandstone)

Clastic Sedimentary Rock (Litharenite/Quartzite transition)

Sandstone (Pebble/Cobble)

Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)

Sandstone (Stream-rounded Cobble)

Arenite (composed primarily of SiO2, Silica)

Pink Granite

Phaneritic Felsic Igneous Rock

Sandstone (specifically Red Sandstone)

Arenite (primarily Quartz, SiO2)

Shale

Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)

Sandstone (specifically Arkose or Ferruginous Sandstone)

Sandstone (SiO2 with iron oxide inclusions)

Quartz Vein in River Siltstone

Crystalline Quartz (SiO2) in Siliclastic Matrix

Shale

Fissile mudstone (Shale)

Chert (specifically tan/pink variety)

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 dominant)

Sandstone (specifically Arkose or Quartz Arenite)

Arenite (primarily SiO2 with possible Feldspar)

Shale

Fissile mudrock (composed of clay-sized particles and detrital grains)

Ferruginous Sandstone Pebble

Arenite with Iron-Oxide Cement (SiO2 with Fe2O3/FeO(OH) staining)

Gneiss (specifically a granitic gneiss cobble)

Gneiss (high-grade regional metamorphic rock)

Sandstone (specifically Lithic or Quartz Arenite)

Arenite (composed primarily of SiO2)

Sandstone (specifically Picture Sandstone or Wonderstone)

Arenite (composed primarily of SiO2)

Petrified Wood

Silicified Wood (SiO2)

Sandstone

Quartz Sandstone (predominantly)

Sandstone Cobble with Liesegang Rings

Arenite with iron oxide precipitation (SiO2 matrix with Fe2O3 banding)

Sandstone (likely Siltstone or fine-grained Sandstone)

Sedimentary Rock (Clastic)

Quartzite (Yellow/Orange variety)

Quartzite (primarily SiO2)

Sandstone (likely Arkosic)

Clastic Sedimentary Rock

River Rock (likely Siltstone or fine-grained Sandstone)

Clastic Sedimentary Rock

Conglomerate (or Breccia)

Clastic Sedimentary Rock

River Pebble (Siltstone/Mudstone)

Clastic sedimentary rock

Sandstone (likely Graywacke or Lithic Sandstone)

Clastic Sedimentary Rock

Chert / Jasper

Microcrystalline Quartz (SiO2)

Sandstone

Sandstone (clastic sedimentary rock)

Chert (Iron-stained)

Chert (Cryptocrystalline Silica, SiO2)