Not A Natural Rock (Man Made Composite)

Chert (Jasper / Quartz pebble)

Microcrystalline Quartz (SiO2)

Sandstone (River Cobble)

Sandstone (primarily composed of silica, SiO2)

Sandstone (Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily Quartz - SiO2)

Sandstone

Arenite (SiO2 based)

Green Sandstone Pebble (River/Beach Pebble)

Glauconitic Sandstone

Quartz Pebble (Chalcedony / Agate)

Silicon Dioxide (SiO2)

Sedimentary Sandstone with Iron Oxide

Ferruginous Sandstone

Granite

Phaneritic intrusive felsic igneous rock

Granite

Granite (Silica-rich Plutonic Rock)

Chert (Chocolate or Brown Flint)

Chert (SiO2)

Granite

Phaneritic plutonic rock (composed of quartz, feldspar, and mica)

Shale (or Mudstone)

Clay mineral aggregate / Fine-grained siliciclastic sedimentary rock

Siltstone or Limestone Beach Pebble

Siltstone / Micritic Limestone

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone

Arenite (primarily SiO2)

Red Sandstone

Arenite (Ferruginous Sandstone)

Sandstone (Ferruginous)

Sandstone (Clastic sedimentary rock, predominantly SiO2 with Fe2O3 cement)

Sandstone (specifically Arkose or Ferruginous Sandstone)

Sandstone (SiO2 predominant)

Sandstone (Quartzose Sandstone)

Clastic sedimentary rock (primarily SiO2)

Sandstone (Feldspathic / Arkose)

Sandstone (SiO2 with variable mineral grains)

Tumbled turquoise-like stone

Likely turquoise, hydrated copper aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone

Arenite (SiO2 based)

River Cobble (likely Metasedimentary)

Metasedimentary Rock / Quartz-rich Sandstone

Sandstone

Arenite (primarily SiO2)

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily Quartz with Hematite/Limonite oxides)

Hag Stone

Porous sedimentary rock (typically Flint, Chert, or Sandstone) with naturally occurring holes

Chert Arrowhead (Lithic Tool)

Microcrystalline quartz (SiO2) - Archeological lithic artifact

Sandstone

Sedimentary Rock (Quartz Sandstone)

Black obsidian (probable)

Volcanic glass; primarily SiO₂-rich rhyolitic composition

Tumbled Mixed Gemstones and Rocks

Various mineral species including quartz (SiO2) and silicate minerals

Ironstone / Hematite Concretion

Iron oxide / Fe2O3

Conglomerate

Polymictic Conglomerate

Ferruginous Sandstone Pebble

Iron-rich Clastic Sedimentary Rock

Sandstone (Quartzose)

Arenite (SiO2 based)

Green Aventurine

Aventurine Quartz (SiO2 with Fuchsite inclusions)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Chert (Green Fossilized Algae or Jasper)

Silicon Dioxide (SiO2)

Shale

Shale (comprised mostly of clay minerals and quartz)

Red Granite

Phaneritic Felsic Igneous Rock

Pink Granite

Granite (Phaneritic intrusive rock)