Crystal

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Desert Rose

Gypsum (variety Selenite) or Barite, CaSO4·2H2O

Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Tumbled chalcedony pebble

Chalcedony, microcrystalline quartz (SiO₂)

Tumbled rose quartz

Quartz, silicon dioxide (SiO₂), pink variety colored mainly by trace iron, titanium, or inclusions

Quartz Geode with Calcite

Silicon Dioxide (SiO2) and Calcium Carbonate (CaCO3)

Small translucent quartz fragment

Quartz (SiO₂), possibly milky or near-colorless quartz

Polished citrine quartz point

Quartz, silicon dioxide (SiO₂), yellow-orange variety commonly sold as citrine; possibly heat-treated amethyst

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Rose Quartz

Silicon Dioxide (SiO2)

Quartz (Milky or White Quartz)

Silicon Dioxide (SiO2)

Limonite Geode / Ironstone Concretion with Quartz

Limonite with Quartz (FeO(OH)·nH2O + SiO2)

Porphyritic Basalt (with Augite Crystals)

Porphyritic Mafic Volcanic Rock (Fe-Mg Silicates)

Pyrite

Iron Sulfide (FeS2)

Bismuth

Native Bismuth (Bi)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Quartz (Silicon Dioxide, SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Quartz (Silicon Dioxide - SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Quartz (Silicon Dioxide, SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Obsidian

Volcanic glass (Amorphous silicon dioxide)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Hematite

Iron(III) oxide (Fe2O3)

Milky Quartz Beads

SiO2 (Silicon Dioxide)

Likely druzy quartz/agate specimen

Quartz (SiO₂), possibly iron-stained chalcedony or agate

Tumbled rose quartz

Rose quartz, silicon dioxide (SiO₂), quartz variety

White quartz fragment

Quartz (silicon dioxide, SiO₂)

Pegmatite

Igneous Pegmatite

Pegmatite

Pegmatitic Granite containing Quartz, Feldspar, and Schorl

Druzy Quartz on Chert/Chalcedony

Silicon Dioxide (SiO2)

Amethyst (Polished/Carved Crystal)

Silicon Dioxide (SiO2) with trace Iron (Fe)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)