Sedimentary (Cryptocrystalline Quartz)

Chert (Tan/Brown variety)

Chert (Microcrystalline Quartz, SiO2)

Desert Varnish on Sandstone

Ferromanganese coating on Quartz Arenite

Yellow Jasper / Chert

Jasper (Silica/Quartz) - SiO2

Sandstone

Arenite (primarily Quartz, SiO2)

Jasper

Jasper (Silica/Quartz) - SiO2

Chert (Green Jasperiod)

Chert (Microcrystalline Quartz, SiO2)

Sandstone

Arenite (primarily Quartz, SiO2)

Quartzite (or Iron-Stained Quartz Pebble)

Silicon Dioxide (SiO2) with Ferric Oxide inclusions

Pietersite

Brecciated Crocidolite in Quartz (Chalcedony)

Clear Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite (composed primarily of SiO2)

Sandstone

Sandstone (clastic sedimentary rock, predominantly SiO2)

Sandstone

Arenite (SiO2 based)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Petrified Wood

Silicified wood (primarily SiO2)

Rough Quartz (likely Rose or Smoky variant)

Silicon Dioxide (SiO2)

Ferruginous Sandstone

Clastic Sedimentary Rock (Iron-rich)

Botryoidal Hematite (included in Quartz/Limonite matrix)

Fe2O3 (Hematite) on Quartz (SiO2) / Limonite

Quartz Druze on Matrix

Silicon Dioxide (SiO2)

Kambaba Jasper (Crocodile Jasper)

Rhyolite containing Fossilized Cyanobacteria (Stromatolite)

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Quartz Pebble (likely Chalcedony or Quartzite)

Silicon Dioxide (SiO2)

Mixed Quartz and Jasper Pebbles

Silicon Dioxide (SiO2)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Quartz Geode

Silicon Dioxide (SiO2)

Pyrite in Quartz

Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)

Sandstone (likely Quartzose Sandstone)

Arenite (SiO2 predominantly)

Sandstone

Arenite (Siliclastic sedimentary rock)

Quartz Geode

Crystalline Silicon Dioxide (SiO2) in a Geodic structure

Clear Quartz

Crystalline Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 staining)

Red Sandstone

Arenite (primarily Quartz with Iron Oxide)

Quartz pebble (Quartztite fragment)

Silicon Dioxide (SiO2)

Quartz Pebble (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Sandstone (likely Quartzose Sandstone)

Arenite (primarily SiO2)

Quartz Druzy (on Calcedony/Quartz base)

Silicon Dioxide (SiO2)

Sandstone (River Cobble)

Arenite

Yellow Jasper

Tectosilicates (SiO2) with Goethite/Iron oxide inclusions