Sedimentary (Secondary Classification: Cryptocrystalline Quartz)

Agate Nodule (partially vuggy Quartz)

Silicon Dioxide (SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline quartz (SiO2)

Chalcedony (Agate/Quartz pebble)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Likely galena-bearing ore or graphite-rich sulfide fragment

Indeterminate; possibly galena (PbS) with quartz, or graphite-rich schist

Jasper with Quartz Veining

Silicon Dioxide (SiO2) with Hematite impurities

Lunar Feldspathic Breccia

Lunar Meteorite (Feldspathic Regolith Breccia)

Jasper with Quartz Veining

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Red Jasper with Quartz Veining

Jasper (Silicon Dioxide, SiO2)

Brecciated Agate / Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Yellow Agate Bottle

Cryptocrystalline Silicon Dioxide (SiO2)

Banded Agate / Jasper (Chert Pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chalcedony

Silicon Dioxide (SiO2)

Jasper with Quartz Veining

Silicon Dioxide (SiO2) with iron oxide inclusions

Chert Pebble (with Quartz Vein)

Chert (Cryptocrystalline Silica - SiO2)

Agate

Silicon Dioxide / Cryptocrystalline Quartz (SiO2)

Limonite-stained Chert

Microcrystalline Quartz (SiO2) with Goethite/Limonite (FeO(OH)·nH2O)

Geode (Chert or Quartz Nodule)

Silicon Dioxide (SiO2)

Beach Agate / Chalcedony Pebble

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Chert (Septarian or Nodular variety)

Microcrystalline Quartz (SiO2)

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, potentially granitic, or recrystallized quartzite

Chert (Iron-stained)

Chert (SiO2)

Road-surface aggregate (crushed stone)

Unidentifiable mixed lithic aggregate; likely basaltic/andesitic fragments with feldspar, quartz, and weathered rock

Feldspar-rich igneous rock, likely granite or gneiss fragment

Granite-like quartz–feldspar rock; exact identification is uncertain from the blurred image

Jasper

Silicon dioxide, SiO2

Quartz Geode in Chert/Limestone Matrix

Silicon Dioxide (SiO2) within Sedimentary Host Rock

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Jasper with Quartz Veining

Silicon Dioxide (SiO2) with impurities

Greenstone / Chert

Cryptocrystalline Quartz (SiO2) or Altered Basalt

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Chert (Flint) with Limonite Staining

Microcrystalline Quartz (SiO2)

Band Agate / Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Weathered granite or granitic gneiss

Quartz–feldspar–mica granitoid; possible biotite granite or gneiss

Quartz (likely Chalcedony or Chert)

Silicon Dioxide (SiO2)

Weathered quartz-bearing rock, possibly granite or gneiss

Indeterminate; likely quartz–feldspar–mica aggregate, possibly granitic gneiss

Chert (Pebble)

Silicon Dioxide (SiO2)

Chalcedony

Silicon dioxide (SiO2) - Microcrystalline quartz

Banded Agate (with possible Chalcedony layers)

Silicon dioxide (SiO2)

Agate

Silicon Dioxide (SiO2)

Chert with Iron Oxide Staining

Microcrystalline Quartz (SiO2) with Limonite/Goethite staining

Jasper with Quartz Veining

Microcrystalline quartz (SiO2) with iron oxide impurities