None

Quartzite

Quartzite (SiO2)

Quartz Geode (Citrine or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Clear Quartz (Herkimer Diamond variant)

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Silicon Carbide (Carborundum)

Moissanite (SiC), though mostly synthetic

Sandstone

Arenite (composed primarily of SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Red Jasper (possibly Petrified Wood)

Silicon Dioxide (SiO2) with Hematite inclusions

Quartz (Milky or Druzy Quartz)

Silicon Dioxide (SiO2)

Specular Hematite (Specularite) in Matrix

Specularite (Fe2O3)

Chert (specifically Yellow or River Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Amethyst (Tumbled)

Quartz (Silicon Dioxide, SiO2) with iron impurities

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)

Milky Quartz

Silicon Dioxide (SiO2)

Rose Quartz and Milky Quartz

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Chert (Flint variety)

Silicon Dioxide (SiO2)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Metasedimentary or Igneous matrix

Cubic Zirconia

Cubic Zirconium Dioxide (ZrO2)

Quartzite

Quartzite (SiO2)

Amethyst (Polished Point)

Crystalline Quartz (SiO2 with iron impurities)

Quartz (Druzy)

Silicon Dioxide (SiO2)

Clear Quartz Point

Silicon Dioxide (SiO2)

Herkimer Diamond

Quartz (Silicon Dioxide, SiO2)

Yellow Jasper

Silicon Dioxide (SiO2) with iron hydroxides

Quartzite Pebble

SiO2 (Silicon Dioxide)

Tiger's Eye

Pseudomorph of quartz after crocidolite (SiO2 with iron oxide inclusions)

Ferruginous Quartz

Silicon Dioxide with Iron Oxide (SiO2 + Fe2O3)

Fossil Coral

Scleractinia (Anthos), primarily Calcium Carbonate (CaCO3)

Clear Quartz

Silicon Dioxide (SiO2)

Blue Agate (Dyed)

Silicon Dioxide (SiO2)

Chert (varieties: Flint or Chalcedony)

Microcrystalline silica (SiO2)

Chert (Flint Pebbles)

Microcrystalline quartz (SiO2)

Sandstone (Ferruginous)

Arenite (with Iron Oxide cement)

Milky Quartz

Silicon Dioxide (SiO2)

Citrine

Silicon Dioxide (SiO2)

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Native Copper (Penny specimen)

Native Copper (Cu)

Prasiolite

Silicon Dioxide (SiO2)

Chert (Flint variety)

Microcrystalline Quartz (SiO2)

Magnetite (Small Granule)

Magnetite (Fe3O4)

Amethyst (Faceted)

Silicon Dioxide (SiO2) with iron impurities