Sedimentary Rock (Specifically A Chemical Sedimentary Rock, Or A Chert If Considered Purely Mineral Aggregate)

Clear Quartz (Rock Crystal)

Quartz (SiO₂)

Quartz Geode

Crystalline Silicon Dioxide (SiO2)

Quartzite

Quartzite (primarily SiO2)

Weathered Basalt with Iron Staining

Mafic Igneous Rock

Quartz on Matrix

Silicon Dioxide (SiO2)

Ferruginous Sandstone

Sandstone with Iron Oxide (Limonite/Goethite)

Chert (White Chert / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (often called Flint)

Silicon Dioxide (SiO2)

Chert (Common Opal/Chalcedony mixture)

Silicon Dioxide (SiO2)

Chert (often called Flint or Jasper based on color)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Breccia

Clastic Breccia (SiO2/CaCO3 dominated)

Sandstone (Ferruginous/Banded)

Clastic Terrigenous Sandstone (SiO2 with Fe2O3 cement)

Chert (often called Flint for darker varieties)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Red Sandstone (Old Red Sandstone Pebble)

Arenite with iron oxide (Fe2O3) cement

Ironstone Concretion (Nutstone)

Ironstone (with High Limonite/Hematite Content)

Granitic Gneiss

Gneiss (high-grade metamorphic rock primarily of quartz, feldspar, and mica)

Concretion (Sandstone)

Sandstone Concretion

Basalt River Stone

Basalt

Chert (varietal: Flint or River Pebble)

Silicon Dioxide (SiO₂)

Chert (specifically Jasper/Carnelian Agate)

Microcrystalline Quartz (SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Conglomerate

Conglomerate (clastic sedimentary rock)

Conglomerate

Conglomerate (clastic sedimentary rock)

Quartz Pebble

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate (Clastic sedimentary rock)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Calcite (Yellow/Orange variety - sometimes called Honey Calcite)

Calcite

Geode (Unopened)

Chalcedony/Quartz Geode (SiO2)

Dalmatian Stone

Dalmatian Jasper (Aplitic Rock)

Ferruginous Sandstone (Iron-rich Sandstone)

Ferruginous Arenite

Quartz (Milky/Bull Quartz)

Silicon Dioxide (SiO2)

Banded Gneiss

Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica)

Mookaite Jasper

Radiolarite (Silicified radiolarian chert), SiO2

Fluorite with Quartz coating

Calcium Fluoride (CaF2) with Silicon Dioxide (SiO2)

Geode (Unopened)

Silicon Dioxide (SiO2) in sedimentary vugs

Limestone

Calcium Carbonate (CaCO3)

Quartz in Matrix (possibly with Biotite or Hornblende)

Quartz (Silicon Dioxide, SiO2) in Granitic Matrix

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Quartz

Silicon Dioxide (SiO2)

River Pebble (Quartz-rich)

Silicon Dioxide (SiO2) with various inclusions

Riverstone (Quartzite or Siltstone cobble)

Quartzite (primarily SiO2)

Feldspathic Gneiss (Granite Gneiss)

Gneiss (High-grade Regional Metamorphic Rock)