Sedimentary (Microcrystalline Quartz)

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

African Turquoise (Jasper)

Polychrome African Jasper (often marketed as 'African Turquoise' due to its color, but it is not true turquoise)

Rock

Quartzite

Quartzite (primarily SiO2)

Quartz

Silicon Dioxide (SiO2)

Crystal Quartz Beads (likely Clear Quartz)

Quartz (SiO₂)

Quartz (likely Milky Quartz or Chalcedony)

Quartz (SiO2 - Silicon Dioxide)

Sedimentary (most likely, as Chert is a sedimentary rock often found as nodules in limestone or as bedded deposits; however, it can also form by metasomatic replacement, which leans towards metamorphic processes under certain conditions)

Chert or Flint (polished/water-worn)

Chert (a microcrystalline or cryptocrystalline variety of quartz, SiO2). Flint is a specific variety of chert.

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily Quartz with Limonite/Goethite staining)

sedimentary

Green Aventurine (Green Quartz)

Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)

Mineral/Metamorphic rock

Pyrite (on host rock)

Iron Sulfide (FeS2)

Milky Quartz

Quartz (Silica / Silicon Dioxide), SiO2

Common Opal in Host Rock

Hydrated Silica (SiO2·nH2O)

mineraloid

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Tiger's Eye

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

Quartz (Milky/Bull Quartz)

Silicon Dioxide (SiO2)

Clear Quartz Cluster

Quartz (Silicon Dioxide - SiO2)

Quartzite

Quartzite (primarily SiO2)

Pink Quartzite

Quartzite (primarily SiO2)

Quartz

Quartz (Silicon Dioxide, SiO2)

Clear Quartz (beads in a bracelet)

Quartz (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Green Agate

Silicon dioxide (SiO₂)

Quartz (likely Clear Quartz or Rock Crystal)

Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Sandstone (Quartzite-rich)

Clastic sedimentary rock (SiO2 primary)

sedimentary

Quartz (Milky Quartz / Quartzite)

Silicon Dioxide (SiO2)

White Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

White Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Quartz (Milky Variant)

Quartz (Silicon Dioxide, SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Mineral (variety of Chalcedony/Quartz)

Red Jasper

Silicon Dioxide with Iron Oxide impurities (SiO2 + Fe2O3)

Quartz Veined Basalt

Mafic Volcanic Rock with Microcrystalline Quartz (SiO2)

igneous

Red Jasper

Silicon dioxide (SiO2)

Agate

Agate (Silicon Dioxide, SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Banded Agate

Cryptocrystalline Quartz (SiO2)

Quartzite Arrowhead (Archaeological Lithic)

Recrystallized Quartz (SiO2)