Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Geode (Unopened)

Silica-rich Concretion (primarily SiO2)

Obsidian

Obsidian (volcanic glass)

Conglomerate (Puddingstone)

Conglomerate (specifically, clastic sedimentary rock)

Red Sandstone (Old Red Sandstone)

Ferruginous Sandstone (SiO2 + Fe2O3)

Banded Calcite (often sold as 'Travertine' or 'Mexican Onyx')

Calcium Carbonate (CaCO3)

Sandstone (Quartz-rich Pebble)

Arenite (primarily SiO2)

Banded Gneiss (with Quartz Vein)

Gneiss (Metamorphic rock of varying mineralogy)

Red Sandstone

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

Sandstone (specifically Cross-bedded Sandstone)

Arenite (composed primarily of SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert / Jasper / Agate (Chalcedony Group)

Microcrystalline Quartz (SiO2)

Sandstone

Arenite (composed primarily of SiO2)

Ironstone Concretion / Goethite-Hematite Nodule

Goethite/Hematite (α-FeO(OH) / Fe2O3)

Laterite

Laterite (Iron and aluminum-rich residual rock)

Jasper Breccia

Brecciated Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)

Bauxite

Bauxite (Al(OH)3, AlO(OH))

Chert (Iron-rich or Jasperoid)

Cryptocrystalline Quartz (SiO2)

Chert (Yellow/Brown Jasper)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Fossiliferous Limestone (Coquina / Shell Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Ferruginous Conglomerate

Conglomerate with Iron-Oxide Matrix (SiO2 + Fe2O3/FeO(OH))

Mica Schist

Mica Schist (Schistose metamorphic rock rich in Muscovite/Biotite)

Conglomerate (River Rock Aggregate)

Conglomerate (Lithic-clast conglomerate)

Granite Cobble

Phaneritic Felsic Igneous Rock (Granite)

Bloodstone

Heliotrope (cryptocrystalline Quartz, SiO2 with inclusions of Hematite)

Jasper and Chert Conglomerate

Ferruginous Microcrystalline Quartz (SiO2)

Sandstone (Red Sandstone)

Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide)

Sandstone (with Liesegang rings or Oxidation)

Arenite (primarily Quartz SiO2 with Iron Oxide Fe2O3 staining)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Red Chert (Jasper)

Silicon Dioxide (SiO2)

Slag Glass

Amorphous Silica / Glass Slag

Petrified Wood

Silicified Wood (SiO2)

Leopard Skin Jasper

Orbicular Rhyolite (Silicon Dioxide with various impurities)

Chert / Flint

Cryptocrystalline Quartz (Silicon Dioxide, SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Red Sandstone

Arenite (Ferruginous Sandstone)

Schist

Mica Schist

Chert (Commonly known as Flint)

Microcrystalline Quartz (SiO2)

Chert (Pink Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Chert (Banded)

Chert (Microcrystalline Silicon Dioxide, SiO2)

Chert (White/Gray variety)

Chert (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)