Sedimentary (Microcrystalline Quartz)

Chert (Beach Pebble)

Silicon Dioxide (SiO2)

Ferruginous Siltstone or Mudstone

Ferruginous Siltstone / Goethitic Sandstone

Sandstone Concretion

Clastic Sedimentary Concretion (primarily SiO2 with Fe2O3 cement)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone (likely Calcareous or Quartz-rich)

Arenite (SiO2 based typically)

Milky Quartz (Ferruginous variety)

Silicon Dioxide (SiO2)

Sandstone

Arenite (Sedimentary rock composed of sand-sized minerals or rock grains)

Quartz (Clear/White)

Silicon Dioxide (SiO2)

Quartz (Milky/Crystalline variety)

Silicon Dioxide (SiO2)

Quartzite

Quartzite (SiO2)

Quartz (Milky/Crystalline)

Quartz (Silicon Dioxide, SiO2)

Granite Sand (Decomposed Granite)

Grus / Quartz-Feldspar Detritus

Clear Quartz

Silicon Dioxide (SiO2)

Yellow Chalcedony (Agate/Chert)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Chert (Flint variety)

Silicon Dioxide (SiO2)

Agate (Slab)

Agate (Cryptocrystalline variety of Quartz, SiO2)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Clear Quartz Cluster

Silicon Dioxide (SiO2)

Clear Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Ferruginous Quartzite (Iron-stained Quartz)

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3)

Quartzite

Quartzite (SiO2)

Chalcedony (Quartz Nodule)

Silicon Dioxide (SiO2)

Druzy Quartz Geode (Oco or Moroccan variety)

Silicon Dioxide (SiO2)

Green Aventurine

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

Gold Nugget

Native Gold (Au)

Agate (Chalcedony)

Cryptocrystalline Silica or Silicon Dioxide (SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite mica

Amethyst

Amethyst (Silicon Dioxide - SiO2 with iron impurities)

Sandstone

Arenite (composed primarily of Quartz, SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Limestone (Weathered)

Calcium Carbonate (CaCO3)

Tree Agate (or Moss Agate)

Dendritic Agate (Silicon Dioxide - SiO2)

Gneiss

Gneiss

Sandstone (Greywacke)

Clastic Sedimentary Rock (SiO2 with lithic fragments)

Granitic Sand

Detrital sediment (predominantly Quartz, Feldspar, and Mica)

Sandstone with Ironstone Banding

Clastic Sandstone (composed of Quartz with Hematite/Limonite bonding)

Yellow Quartzite (River Pebble)

Quartzite (primarily SiO2)

Conglomerate

Clastic Sedimentary (Conglomerate)

Conglomerate

Conglomerate (clastic sedimentary rock)

Sandstone (likely Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Sandstone

Clastic Sedimentary Rock (composed mostly of quartz and/or feldspar)