Sedimentary (Cryptocrystalline Quartz)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Common Opal in Host Rock

Hydrated Silica (SiO2·nH2O)

Quartz-veined Sedimentary Rock

Hydrothermally veined Clastic Sedimentary Rock (SiO2 veins in Matrix)

Agate

Silicon Dioxide (SiO2) - Banded Chalcedony

Quartz (Milky/Bull Quartz)

Silicon Dioxide (SiO2)

Clear Quartz Cluster

Quartz (Silicon Dioxide - SiO2)

Blue Chalcedony

Silicon Dioxide (SiO2)

Chalcedony (Agate)

Silicon Dioxide (SiO2)

Agate (Carnelian / Chalcedony)

Silicon Dioxide (SiO2)

Chert (Flint variety)

Chert (SiO2)

Carnelian (Chalcedony)

Silicon Dioxide (SiO2)

Chert (Flint variety)

Silicon Dioxide (SiO2)

Jasper (Chert)

Silicon Dioxide (SiO2)

Clear Quartz (beads in a bracelet)

Quartz (SiO2)

Quartz

Quartz (Silicon Dioxide, SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (likely Clear Quartz or Rock Crystal)

Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Chert (Nodular)

Microcrystalline Silica (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Polished Chert (Flint)

Silicon Dioxide (SiO2)

Jasper (Green variety)

Silicon Dioxide (SiO₂)

Chert (Black Chert/Flint)

Silicon Dioxide (SiO2)

Chert (Quartzite-rich River Pebble)

Silicon Dioxide (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (Chalcedony)

Silicon Dioxide (SiO2)

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Chert (Field Stone)

Chert (Silicon Dioxide, SiO2)

Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Chert / Flint

Silicon Dioxide (SiO2)

Chert (Flint)

Chert (Silicon Dioxide, SiO2)

Chert (Grey-Green Var.)

Silicon Dioxide (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Picture Jasper

Silicon Dioxide (SiO2) with iron oxide and mineral impurities

Chert (Arrowhead Debitage or Flake)

Microcrystalline silica (SiO2)

Chert (Nodule)

Chert (composed of Microcrystalline Silica/SiO2)

Chert (Iron-stained)

Silicon Dioxide (SiO2)

Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Chert (varieties include Jasper or Flint)

Chert (Microcrystalline Silica, formula: SiO2)

Jasper

Jasper (Silicon Dioxide, SiO2)

Chert (and Limestone)

Silicon Dioxide (SiO2)