Sedimentary Rock (Possibly Conglomerate Or Breccia With A Quartz Vein)

Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')

Calcite (Calcium Carbonate, CaCO3)

Red Sandstone

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

Green Aventurine and Clear Quartz

Aventurine (variety of Quartz - SiO2) and Quartz (SiO2)

Chert (Hagstone/Adder Stone)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (Quartz-rich)

Arenite (composed primarily of SiO2)

Cherry Creek Jasper (also known as Red Creek Jasper or Cherry Creek Agate)

Jasper, microcrystalline quartz (SiO₂)

Chalcedony in Matrix

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Agate

Chalcedony (cryptocrystalline variety of Quartz, SiO2)

Jasper (Red Jasper)

Silicon Dioxide (SiO₂)

Chert (Iron-Stained)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Red Jasper

Silicon dioxide (microcrystalline quartz with iron oxide inclusions), SiO2

Petrified Wood

Silicified Wood (SiO2)

Sandstone (Quartz-rich Pebble)

Arenite (primarily SiO2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Ferruginous Sandstone (Red Sandstone)

Arenite with Hematite/Limonite cement

Sandstone (Ferruginous)

Arenite with Iron-Oxide Cement (primarily SiO2 with Fe2O3/FeOOH)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (specifically Banded Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 based with mineral cement)

Quartzite with Chert inclusions

Metamorphosed Quartz-rich Rock (SiO2)

Banded Agate

Silicon Dioxide (SiO2) - Chalcedony variety

Amethyst Geode

Silicon Dioxide with trace inclusions of Iron (SiO2)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Quartz (milky quartz variety)

Quartz (SiO₂)

Ferruginous Sandstone

Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)

Chert (White-Tan variety)

Silicon dioxide (SiO2) / Microcrystalline Quartz

Bumblebee Jasper

Fossiliferous Calcite containing Orpiment and Realgar

Orbicular Rhyolite (Rainforest Jasper)

Rhyolite containing Spherulites (SiO2 with impurities)

Sandstone (Ferruginous)

Ferruginous Sandstone (SiO2 with iron oxide cement)

Sandstone (likely Quartzose)

Clastic sedimentary rock (SiO2 primary)

Gneiss

Gneiss

Gneiss

Gneiss (High-grade Metamorphic Rock)

Clear Quartz Crystal

Silicon Dioxide (SiO2)

Carnelian

Chalcedony (cryptocrystalline quartz), SiO2

Gneiss

High-grade metamorphic rock (Gneiss)

Granitic Gneiss

Gneiss (containing Potassium Feldspar and Quartz)

Milky Quartz (with trace inclusions)

Silicon Dioxide (SiO2)