Sedimentary (Cryptocrystalline Silica)

Dendritic Agate (also known as Dendritic Siltstone or Mudstone)

Silicon Dioxide with Manganese/Iron Oxide inclusions (SiO2 + MnO2)

Jasper Geode

Silicon Dioxide (SiO2) with impurities

Red Jasper

Silicon Dioxide (SiO2) with iron inclusions

Agate (translucent pebble)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Chert (often called Flint)

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily SiO2)

Ocean Jasper

Orbicular Jasper/Microcrystalline Quartz (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Red Chert

Microcrystalline Quartz (SiO2)

Chert (often called Jasper in this color)

Microcrystalline quartz (SiO2)

Chert (variously identified as Flint)

Microcrystalline Quartz (SiO2)

Bauxite

Bauxite (Principal ore of aluminum; mixture of minerals including Gibbsite Al(OH)3, Boehmite and Diaspore AlO(OH))

Jasper with Epidote

Silicon Dioxide (SiO2) with Calcium Aluminum Iron Silicate (Ca2(Al,Fe)3(SiO4)3(OH))

Chert (Field Stone/Jasper variety)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Blue Lace Agate

Agate (Variety of Chalcedony, SiO2)

Jasper Conglomerate

Jasper Conglomerate (SiO2 matrix with varying mineral inclusions)

Bauxite

Al2O3·2H2O (principally composed of gibbsite, boehmite, and diaspore)

Chert (Common Opal/Agate mixture)

Microcrystalline Quartz (SiO2)

Banded Iron Formation (BIF)

Banded Iron Formation (Magnetite-Hematite-Chert)

Quartzite (River Stone)

Quartzite (mainly SiO2 with iron oxide staining)

Sandstone

Arenite (primarily SiO2)

Sandstone

Arenite (SiO2 based)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone (Ferruginous)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 cement)

Sandstone (Yellow/Siltstone variant)

Arenite (SiO2 primarily)

Banded Calcite (Mexican Onyx)

Calcium Carbonate (CaCO3)

Turquoise

Turquoise (CuAl6(PO4)4(OH)8·4H2O)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silica / Silicon Dioxide, SiO2)

Chert (Beach Pebble)

Silicon Dioxide (SiO2)

Ferruginous Quartz

Quartz with Iron Oxide inclusions (SiO2 + Fe2O3)

Breccia

Breccia (Clastic Sedimentary Rock)

Sandstone

Arenite (composed primarily of SiO2)

Red Jasper

Silicon Dioxide (SiO2) with Hematite (Fe2O3) impurities

Yellow Jasper

SiO2 (Silicon Dioxide)

Sandstone with Quartz Vein

Arenite with SiO2 intrusion

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix

Milky Quartz Geode or Druzy Quartz

Silicon Dioxide (SiO2)

Sandstone (Quartzose)

Arenite (composed mainly of SiO2)

Sandstone (with Concretion)

Arenite / Quartzose Sandstone

Fossilized Turritella Gastropod (Internal Mold)

Turritella (Fossil Gastropod Crust)