Sedimentary Or Metamorphic (Base Substrate)

Sandstone

Arenite (primarily SiO2)

Chert Arrowhead

Microcrystalline Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite (Secondary classification based on grain size)

Precious Opal

Hydrated Silica (SiO2·nH2O)

Siltstone

Siltstone (primarily SiO2, Al2O3)

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)

Chalcedony (Botryoidal)

Silicon Dioxide (SiO2)

Green Aventurine

Aventurine Quartz (SiO2 with Fuchsite inclusions)

Fossilized Shark Tooth

Fossilized Elasmobranchii tooth (likely Odontaspis or Carcharias)

Sandstone

Arenite (SiO2 based typically)

Sandstone

Arenite (SiO2 based typically)

Mica Schist

Mica Schist (Predominantly Muscovite/Biotite)

Mica Schist

Muscovite/Biotite Schist

Quartz with Mica (Gneissic or Pegmatitic origin)

Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(F,OH)2)

Serpentine

Antigorite, Lizardite, or Chrysotile (Mg, Fe)3Si2O5(OH)4

Mica Schist

Mica Schist

Quartzite

Quartzite (SiO2)

Leopard Skin Jasper

Jasper (Silicon Dioxide with impurities), SiO2

Limestone

Calcium Carbonate (CaCO3)

Mica Schist

Muscovite/Biotite Schist

Flesh-toned Siltstone

Siltstone (composed of microscopic Quartz and Feldspar grains)

Limestone (specifically Dolomitic/Crystalline Limestone)

Sedimentary Carbonate Rock (CaCO3 / CaMg(CO3)2)

Limestone Fragment

Sedimentary rock (primarily Calcium Carbonate, CaCO3)

Mica Schist

Mica Schist (primarily Muscovite or Biotite KAl2(AlSi3O10)(OH)2)

Schist

Mica Schist

Sandstone (Weathered Pebble)

Arenite (composed primarily of SiO2)

Quartz / Common Gravel

Silicon Dioxide (SiO2)

Sandstone (likely Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Conglomerate

Polymictic Conglomerate

Schist

Mica Schist (primarily Muscovite and Quartz)

Chert (often colloquially called Flint)

Chert (Microcrystalline Quartz, SiO2)

Schist (Graphite or Mica rich)

Crystalline Schist (often containing Muscovite, Biotite, or Graphite)

Ferruginous Sandstone Pebble

Arenite with Iron Oxide matrix

Limestone (Micrite/Chalky variety)

Calcium Carbonate (CaCO3)

Bituminous Coal

Organic Sedimentary Rock (Carbon-based)

Anthracite Coal

Anthracite (Carbon C)

Banded Metamorphic Rock (likely Quartzite or Serpentinite/Soapstone)

Metamorphic Rock (possibly a banded Quartzite or a foliated Serpentinite/Talc Schist based on appearance, general term for such a rock is 'Banded Metamorphic Rock' or 'Gneiss' if pronounced banding of different minerals)

Mica (Muscovite)

Potassium aluminum silicate - KAl2(AlSi3O10)(OH)2

Coquina / Fossiliferous Limestone

Coquina (composed primarily of Calcium Carbonate / CaCO3)

Bloodstone (Heliotrope)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Druzy Quartz (on Chalcedony/Agate base)

Silicon Dioxide (SiO2)