Limestone

Banded Sandstone (Quartzite-rich)

Clastic Sedimentary Rock (SiO2 with Iron Oxide impurities)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (Chert / Flint nodule)

Silicon Dioxide (SiO2)

Chert (Gravel specimen)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Limonite-stained Chert

Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)

Chert (variations include Flint/Jasper)

Cryptocrystalline Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily SiO2)

Chert (varietal Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Basalt (Water-worn pebble)

Basalt (Mafic Extrusive Rock)

Chert (specifically Black Chert or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Tufa

Calcareous Tufa (Calcium Carbonate, CaCO3)

Green Chert (Jasper)

Silicon Dioxide (SiO2)

Granite (Pink/Potassium-rich)

Phaneritic Plutonic Felsic Igneous Rock (primarily SiO2 with KAlSi3O8)

Fossilized Shark Tooth (Dermal Denticle or worn tooth fragment)

Elasmobranchii (fossil remains)

Geode (Unopened)

Silica-lined Vug (primarily SiO2)

Chert (variant of Flint)

Chert (SiO2)

Yellow Jade (Nephrite or Quartzite)

Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2) or Jade-colored Quartzite (SiO2)

Blue Apatite

Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)

Yellow Jade (Nephrite or Jadeite)

Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2 or Jadeite: NaAlSi2O6

Turquoise in Matrix

Hydrous phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O

Nephrite Jade

Ca2(Mg,Fe)5Si8O22(OH)2

Nephrite Jade

Tremolite-Actinolite solid solution, Ca2(Mg,Fe)5Si8O22(OH)2

Turquoise in Matrix

Hydrated phosphate of copper and aluminium: CuAl6(PO4)4(OH)8·4H2O

Black Spinel

Magnesium Aluminum Oxide (MgAl2O4)

Septarian Nodule (Thunder Egg)

Septarian Concretion (CaCO3 + CaMg(CO3)2 + SiO2)

Septarian Nodule (Dragon Stone)

Septarian concretion (Complex of Calcite, Aragonite, and Limestone/Clay)

Chert (variously Flint or Jasper gravel)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (Nodule)

Chert (Alpha-Quartz, SiO2)

Chert (variations include Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert Pebble / Brachiopod Fossil Internal Mold

Silicon Dioxide (SiO2) / Fossil: Brachiopoda (generic internal mold)

Honey Calcite Geode Segment

Calcite (Calcium Carbonate, CaCO3)

Fossilized Coral

Scleractinian Anthozoa (Fossilized Calcium Carbonate, CaCO3)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (Field Stone)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Fossilized Gastropod (Snail)

Class Gastropoda (internal mold or 'steinkern')

Chert (Hagstone/Gasket Rock variant)

Chert (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Brown variety)

Silicon Dioxide (SiO2)

Grey Quartzite Pebble

Quartzite (primarily SiO2 - Silicon Dioxide)

Chert (Yellow Jasper variant)

Silicon Dioxide (SiO2)

Chert (specifically Chert Nodule/Flint)

Chert (Silicon Dioxide, SiO2)