Rock (Likely Sedimentary)

Sandstone

Arenite (primarily Quartz Arenite)

Sandstone (likely Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Sandstone

Arenite (specifically Iron-stained Quartz Sandstone)

Weathered schist or phyllite

Mica schist/phyllite, likely quartz–mica-rich metamorphic rock

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Pet Rock (Quartzite/Sandstone River Rock)

Silicon Dioxide (SiO2) mixture

Sandstone

Arenite (primarily Quartz and Feldspar composition)

River Rock (Mossy)

Stream-rounded Clast (likely Siltstone or Sandstone with bryophytes)

Quartz Druze (Crystalline Quartz)

Silicon Dioxide (SiO2)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Rounded brown-gray stone, possibly weathered conglomerate or sandstone

Indeterminate clastic sedimentary rock; likely poorly cemented sandstone/conglomerate

Limestone with Lichen

Carbonate Sedimentary Rock (primarily CaCO3)

Chert (Jasper/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Painted River Pebble (likely Basalt or Greywacke)

Aphanitic Lithic Clast with Anthropogenic Pigment coating

Geode (Unopened)

Silicon Dioxide (SiO2) in sedimentary vugs

Sandstone (likely Calcareous or Quartz-rich)

Arenite (SiO2 based typically)

Sedimentary rock with quartz veining

Laminated siltstone or mudstone with hydrothermal quartz veins

River Pebbles (Mixed Lithology)

Conglomerate clasts (Silica-rich and Metamorphic assemblages)

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Jasper (Iron-stained Chert)

Silicon Dioxide (SiO2) with iron oxide inclusions

River Cobble (Sandstone)

Arenite (primarily SiO2)

Granite

Phaneritic Igneous Rock (Granite)

Mixed river stones and gravel

Polymictic alluvial clasts; individual pieces may include quartzite, granite, basalt, sandstone, limestone, and slate

Sandstone (likely Arkosic)

Arenite (SiO2 with KAlSi3O8)

Sandstone

Arenite (primarily Quartz Sandstone)

River Stone (composed of Siltstone/Basalt mixture)

Siltstone or microcrystalline Basalt pebble

Limestone with Algal/Lichen Colonization

Calcium Carbonate (CaCO3)

Sandstone (likely Greywacke or Lithic Sandstone)

Arenite / Wacke

Sandstone (Micaceous)

Arenite (composed primarily of SiO2)

Sandstone (likely Calcareous or Micaceous)

Clastic sedimentary rock (primarily Quartz with Cementing Agents)

Chert (Jasper/Agate variety)

Cryptocrystalline Quartz (SiO2)

Fossiliferous Shale

Laminated Mudrock with plant fossils

Fossiliferous Sedimentary Rock (Coquina/Limestone)

Fossiliferous Calcarenite / Bioclastic Limestone

Fossiliferous Limestone

Calcium Carbonate (CaCO3)

Limitation Concretion

Ironstone Concretion (Goethite/Limonite)

Chalcedony (Common Agate)

Silicon Dioxide (SiO2)

Quartz Vein in Siltstone

SiO2 (Quartz) on clastic sedimentary matrix

Sandstone (lithic wake or graywacke)

Clastic sedimentary rock (primarily quartz and lithic fragments)

Rounded sandstone pebble

Quartz-rich sandstone (likely arkosic or lithic sandstone)

Sandstone (Weathered Pebble)

Arenite (SiO2 primarily)

Sandstone (Weathered Cobble)

Clastic Sedimentary Rock (primarily SiO2)

Sandstone (Quartz-rich)

Clastic sedimentary rock (SiO2 primary)