Sedimentary Rock (Specifically A Chemical Sedimentary Rock, Or A Chert If Considered Purely Mineral Aggregate)

Chert Pebble

Microcrystalline or cryptocrystalline Quartz (SiO2)

Sandstone Chert Concretion

Silica-cemented Concretion (primarily SiO2)

Agate (specifically, a slice of a Blue Lace or Chalcedony Agate nodule)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Chert / Yellow Jasper

Silicon Dioxide (SiO2)

Chert (Iron-stained)

Chert / Microcrystalline Silicon Dioxide (SiO2)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone (lithic wacke)

Arenite / Lithic Wacke (mostly SiO2 with rock fragments)

Rough Quartz in Pegmatite Matrix

Quartz (Silicon Dioxide - SiO2) in Granitic Pegmatite

Chert (Jasper/Chalcedony)

Microcrystalline Quartz (SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Chert (specifically Flint or Common Opal variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Milky Quartz (Common Quartz)

Quartz (Silicon Dioxide, SiO2)

Chert (Chert / Flint nodule)

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate (Detrital Sedimentary Rock)

Conglomerate

Conglomerate rock

Chert (Banded)

Microcrystalline Quartz (SiO2)

Grey Limestone Pebble

Limestone (Calcium Carbonate - CaCO3)

Sandstone (Graywacke)

Arenite / Graywacke (SiO2 with lithic fragments)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Sandstone

Arenite (SiO2 primarily)

Chert (Jasper/Agate variety)

Silicon Dioxide (SiO2)

Agate (specifically Botswana or Lake Superior style chalcedony)

Silicon Dioxide (SiO2)

Chert (Flint variety)

Silicon Dioxide (SiO2)

Chert (Jasper/Common Chert Pebble)

Microcrystalline Quartz (SiO2)

Desert Varnish (on Sandstone)

Rock Varnish (composed of Manganese oxides, Iron oxides, and Clay minerals)

Chert (Flint variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Chalcedony

Silicon Dioxide (SiO2)

Chert (Gravel)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Milky Quartz

Silicon Dioxide (SiO₂)

Chert (Flint Nodules)

Chert (Cryptocrystalline variety of Quartz, SiO2)

Yellow Calcite

Calcium Carbonate (CaCO3)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Ironstone (Limonite/Hematite)

Ferruginous sedimentary rock (Fe2O3·nH2O / Fe2O3)

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (likely Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Chert / Jasper

Microcrystalline Quartz (SiO2)