Sedimentary Rock

Quartz (Milky or Clear variety)

Silicon Dioxide (SiO2)

Jasper (Iron-stained Quartz)

Silicon dioxide (SiO2) with iron oxide inclusions

Geode (unopened)

Calcedony-lined Geode (SiO2)

Milky Quartz (Druzy Geode fragment)

Silicon Dioxide (SiO2)

Red Sandstone

Arenite (primarily Quartz, SiO2, with Iron Oxide cementing agent)

Marble

Recrystallized Carbonate Rock (CaCO3)

Ironstone Concretion / Limonite-stained Siltstone

Ironstone (primarily Limonite FeO(OH)·nH2O and Siltstone)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Gneiss (specifically Banded Gneiss)

Gneiss

Chert Nodule

Chert (Cryptocrystalline variety of Quartz, SiO2)

Ferruginous Sandstone (Ironstone)

Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)

Sandstone (with Iron Oxide)

Arenite with Limonite/Hematite staining

Red Jasper (Brecciated or Mottled)

Silicon Dioxide (SiO2) with iron oxide inclusions

Black Veined Jasper (Spiderweb Jasper)

Silicon Dioxide (SiO2)

Chert (Flint variety)

Chert (SiO2)

Honeycomb Coral Fossil

Favosites (extinct genus of tabulate coral)

Sandstone (Red/Brown Variety)

Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)

Yellow Chert (Gold-toned Jasper)

Silicon Dioxide (SiO2)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Schist (Micaceous Schist)

Schist (comprising Muscovite/Biotite mica, Quartz, and Feldspar)

Conglomerate (River Rock Aggregate)

Conglomerate (Lithic-clast conglomerate)

Ammonite Fossil (Polished Half)

Ammonoidea (subclass)

Sandstone Clast

Arenite (primarily SiO2)

Clear Quartz Cluster

Silicon Dioxide (SiO2)

Gneiss

Gneiss

Granitic Gneiss

Gneiss (High-grade Metamorphic Rock)

Jasper and Agate

Microcrystalline Quartz (SiO2)

Gneiss (Metamorphic Rock)

Gneiss

Granite Gneiss

Gneiss (High-grade Metamorphic Rock)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (Milky or White Quartz)

Silicon Dioxide (SiO2)

Chert (often called Flint or Jasper depending on color)

Chert (SiO2 - Microcrystalline or Cryptocrystalline Quartz)

Chert (River Cobble)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Fossiliferous Limestone (Coquina)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Agate

Agate (Silicon Dioxide - SiO2)

Gneiss (with Quartzite and Mica)

Gneiss

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Quartz Geode (Druzy)

Crystalline Silicon Dioxide (SiO2)

Quartz (Milky/Clear Quartz)

Silicon Dioxide (SiO2)

Gneiss (specifically Granitic Gneiss)

Gneiss (composed primarily of Quartz, Feldspar, and Biotite/Amphibole)

Granitic Sand

Detrital sediment (predominantly Quartz, Feldspar, and Mica)

Tree Agate

Silicon Dioxide (SiO2) with Chlorite inclusions