Sedimentary Rock (Technically A Microcrystalline Quartz Mineral Aggregate)

Sandstone

Arenite (primarily SiO2)

Yellow Chalcedony

Silicon Dioxide (SiO2)

Quartz Vein in Host Rock

Quartz (SiO2) in Mafic or Sedimentary Matrix

Carnelian

Carnelian (Silicon Dioxide - SiO2)

Chert Pebble/Nodule

Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)

River Jasper (Chert/Chalcedony mix)

Silicon Dioxide (SiO2) with iron oxide and chlorite inclusions

Amygdaloidal Rhyolite (often called Lake Superior Agate relative)

Rhyolite with Calcite/Quartz amygdules (SiO2 and secondary minerals)

Mookaite Jasper

Radiolarite (Silicon Dioxide, SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Jasper with Quartz Veining

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Sandstone with Magnetite and Iron Staining

Clastic Sedimentary Rock (contains Fe3O4 and Limonite/Hematite)

Sandstone (Greywacke/Lithic Sandstone)

Arenite (composed primarily of SiO2)

Banded Gneiss

Gneiss (high-grade metamorphic silicate rock)

Jasper with Quartz inclusions

Silicon Dioxide (SiO2)

Quartz Geode (River Cobble)

Silicon Dioxide (SiO2)

Quartz (Milky/Clear Variety)

Silicon Dioxide (SiO2)

Chert / Quartz Pebble

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Clear Quartz

Silicon dioxide (SiO2)

Zebra Jasper

Silicon dioxide (SiO2) with various impurities

Quartz Pebble

Silicon Dioxide (SiO2)

Concretion with Quartz Veining

Septarian Concretion (CaCO3 / SiO2)

Quartzite Pebble

Quartzite (SiO2)

Chert (often called Flint or River Rock)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (Quartz Arenite)

Sandstone (Chemical formula: primarily SiO2)

Sandstone (with potential iron-oxide weathering)

Arenite (SiO2 based)

Blue Chalcedony

Chalcedony (SiO2)

Moss Agate and Druzy Quartz Carving

Cryptocrystalline Silica (SiO2) with impurities

Chert (Flint)

Microcrystalline Quartz (SiO2)

River Rock (River Cobbles)

Fluvial Conglomerate Clasts (primarily composed of various minerals such as Quartz, SiO2)

Jasper (Yellow Jasper)

Silicon Dioxide (SiO2) with iron inclusions

Red Chert (Jasper)

Silicon Dioxide (SiO2)

Chert (with Quartz vein/coating)

Microcrystalline Quartz (SiO2)

Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Sandstone (with minor quartz and possible clay components)

Clastic Sedimentary Rock (SiO2 dominated)

Blue Chalcedony

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz on Matrix

Silicon Dioxide (SiO2)

Quartz

Quartz (SiO2)

Pebble (likely Sandstone or Granitic Pebble)

Clastic Sediment (or specific rock type, e.g., Arenite, Granitoid Pebble)

Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Sandstone

Quartz Sandstone (predominantly)

Granular Sandstone

Arenite (variable composition, primarily SiO2)