Sedimentary (Secondary Classification: Cryptocrystalline Quartz)

Sandstone with Quartz Veining

Clastic sedimentary rock (SiO2 dominated)

Blue Chalcedony

Silicon Dioxide (SiO2)

Green Onyx (Banded Calcite)

Travertine (CaCO3 - Calcium Carbonate)

Chert (often called Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Jasper

Quartz (SiO2) with impurities

Banded Chert or Agate

Silicon Dioxide (SiO2)

Geode (Unopened)

Siliceous Septarian Concretion / Geode (SiO2)

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium) - CuAl6(PO4)4(OH)8·4H2O

Blue Chalcedony

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartz Geode

Silicon Dioxide (SiO2) in Geode form

Carnelian (Chalcedony)

Silicon Dioxide (SiO2) with Iron Oxide impurities

Quartz

Quartz (SiO₂ - Silicon Dioxide)

Agate (Grey Agate Slice)

Microcrystalline Quartz (SiO2)

Granite

Granite (a broadly defined plutonic igneous rock, often more specifically classified as quartz monzonite or granodiorite based on precise mineral percentages)

Jasper

Silicon dioxide (SiO2)

Blue Chalcedony

Silicon Dioxide (SiO2)

Chert (Green variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (Iron-stained)

Chert (Cryptocrystalline Quartz, SiO2)

Chert (Jasper/Flint variation)

Chert (SiO2)

Banded Slate or Siltstone with Quartz/Calcite Veins

Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)

Red Jasper

Silicon Dioxide (SiO₂)

Shiva Lingam

Cryptocrystalline Quartz (Jasproid/Chalcedony mix)

Yellow Jasper

Silicon dioxide (SiO2)

Dyed Agate

Silicon Dioxide (SiO2) with synthetic dyes

Chert (specifically Flint or Common Opal variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint variety)

Chert (Cryptocrystalline Quartz, SiO2)

Chert (Chalcedony/Flint)

Silicon Dioxide (SiO2)

Banded Iron Formation (BIF) with Quartz

Banded Iron Formation, often composed of alternating layers of hematite (Fe2O3) or magnetite (Fe3O4) and chert (microcrystalline quartz, SiO2)

Chert

Chert (variant of microcrystalline quartz)

Limonite and Goethite (Ironstone)

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

Pebble (likely Quartz or Chert)

SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.

Sandstone (with Limonite staining)

Arenite (FeOx-rich)

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (often called Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Banded River Rock / Gneiss (highly weathered)

Gneiss

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Agate and Amethyst (Quartz variants)

Silicon Dioxide (SiO2) - Microcrystalline Quartz and Crystalline Quartz

Ferruginous Quartz

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Chert (Flint variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (specifically Gray Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (River Cobble)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Quartz Geode

Crystalline Quartz (Silicon Dioxide, SiO2)