Sedimentary (Microcrystalline Silicate)

Megalodon Shark Tooth Fossil

Otodus megalodon

Fossil Shark Tooth (Otodus obliquus)

Otodus obliquus; hydroxyapatite (mineralized form Ca5(PO4)3(OH))

Milky Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO₂)

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(OH)2

White Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Chert Nodule

Chert (Cryptocrystalline variety of Quartz, SiO2)

Milky Quartz (or Vein Quartz)

Silicon Dioxide (SiO2)

Chalcedony (Pink/Gray variety)

Silicon Dioxide (SiO2)

Quartz Geode

Quartz (Silicon Dioxide, SiO2) Geode

Quartz (Milky Quartz)

Silicon Dioxide (SiO₂)

Chalcedony (Botryoidal or Geode form)

Silicon Dioxide (SiO2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Chert (specifically Yellow/Honey Jasper variety)

Cryptocrystalline Quartz (SiO2)

Quartz (Milky/Smoky variety)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Clear Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Chalcedony (Agate/Carnelian precursor)

Chalcedony (Silicon Dioxide, SiO2)

Opal

Hydrated amorphous silica (SiO2·nH2O)

Carnelian

Carnelian (Silica, SiO2)

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Quartz

Silicon Dioxide (SiO2)

Agate

Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony

Carnelian

Carnelian (Silicon Dioxide, SiO2)

Quartz (Milky or Rough Quartz)

Silicon Dioxide (SiO2)

Quartz (likely Yellow/Orange variety, possibly Citrine or Chalcedony with iron staining)

Quartz (SiO₂)

Banded Agate (Jasper-Agate)

Silicon Dioxide (SiO₂)

White Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Black Opal

Hydrated Silica (SiO2·nH2O)

Quartz (Druzy on Matrix)

Silicon Dioxide (SiO2)

Carnelian Agate

Silicon Dioxide (SiO2) - variety of Chalcedony

White Onyx (Marble Onyx)

Calcite (CaCO3) - Banded Calcium Carbonate

Geode (Quartz)

Silicon Dioxide (SiO2)

Precious Opal

Hydrated Silica (SiO2·nH2O)

Quartz Pebble (Geode-like)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Pink Opal (Common Opal)

Amorphous Hydrated Silica (SiO2·nH2O)