Sedimentary Rock (Technically A Microcrystalline Quartz Mineral Aggregate)

Sandstone Beach Pebble

Clastic Sedimentary Rock (primarily Quartz with Iron Oxide coating)

Sandstone

Arenite (SiO2 primarily)

Limonite-stained Chert

Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)

Chert (Nodule)

Silicon Dioxide (SiO2)

Sandstone

Sandstone (lithified arenite/wacke)

Banded Agate (Polished Slice)

Chalcedony (cryptocrystalline Quartz), SiO2

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Sandstone

Arenite (primarily SiO2 - Silicon Dioxide)

Quartzite (specifically a river-worn pebble)

Quartzite (primarily SiO2)

Banded Iron Formation (BIF) with Quartz

Banded Iron Formation, often composed of alternating layers of hematite (Fe2O3) or magnetite (Fe3O4) and chert (microcrystalline quartz, SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline Quartz (SiO2)

Snowflake Obsidian

Obsidian with Cristobalite inclusions (Amorphous SiO2 + SiO2 inclusions)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Quartzite

Quartzite (SiO2)

Sandstone (Quartz-rich)

Arenite (SiO2 based clastic rock)

Chert (specifically Tan Chert)

Chert (SiO2)

Chert (Common Opal/Jasper variety)

Microcrystalline Quartz (SiO2)

Chert Nodule

Microcrystalline Quartz (SiO2)

Glauconitic Sandstone (Greensand)

Glauconitic Sandstone ((K, Na)(Fe3+, Al, Mg)2(Si, Al)4O10(OH)2)

Quartzite with Quartz Geode / Vug

Crystalline Silicon Dioxide (SiO2) in Metamorphic Host

Chert (specifically Red Chert or Jasper)

Microcrystalline Quartz (SiO2)

Chert (Common Opal/Agate mixture)

Microcrystalline Quartz (SiO2)

Carnelian

Chalcedony (cryptocrystalline quartz), SiO2

Chert (Honey Chert or Chalcedony Pebble)

Cryptocrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Quartzite River Pebble

Metamorphosed Quartz Sandstone (SiO2)

Chert (Jasper or Flint variant)

Chert (composed of microcrystalline quartz, SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Yellow Jasper

Cryptocrystalline quartz (SiO2) with iron inclusions

Lapis Lazuli

Na8(Al6Si6O24)S2 (Lazurite is the primary constituent mineral)

Wishing Stone (Basalt/Greywacke with Quartz Vein)

Basalt or Siltstone with SiO2 (Quartz) hydrothermal intrusion

Green Jasper

Silicon Dioxide (SiO2) with impurities

Milky Quartz

Silicon Dioxide (SiO2)

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Green Aventurine (likely)

Silicon dioxide (SiO2) with fuchsitemica inclusions

Jasper with Quartz Veining

Silicon Dioxide (SiO2) - Opaque cryptocrystalline variety of Quartz

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Banded Chert

Microcrystalline Quartz (SiO2)

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Gray Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Chert (Brown Variety)

Microcrystalline quartz (SiO2)