Limestone

Fluorite

Calcium fluoride (CaF2)

Epidote

Epidote - {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)

Chert (Arrowhead or Flake)

Microcrystalline quartz (SiO2)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Chert (SiO2)

Chert (variations include Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Hag Stone

Flint / Chert / Limestone concretion with a natural hole

Calcite

Calcite (CaCO₃)

Coquina or Fossiliferous Limestone

Fossiliferous Limstone (CaCO3)

Limestone with Fossil Inclusion

Calcium Carbonate (CaCO3)

Dragon Stone

Ohko Stone (Argillaceous sedimentary rock)

Chert (Jasper/Black Chert)

Silicon Dioxide (SiO2)

Chert (often called Flint or River Pebble)

Microcrystalline Quartz (SiO2)

Zebra Jasper (Zebra Stone)

Tumbled Silicon Dioxide (SiO2) with impurities

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Quartzite

Metamorphosed sandstone (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)

Chert (often called Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Orange Calcite

Calcite (Calcium Carbonate - CaCO3)

Quartzite Cobble

Quartzite (predominantly SiO2)

Chert (Chalk-associated Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Limestone (specifically Grainstone or Micrite)

Calcium Carbonate (CaCO3)

Fairburn Agate / Agate-bearing Breccia

Cryptocrystalline Quartz (SiO2) within Jasper/Breccia matrix

Chert (Yellow or Tan variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (or Chalcedony)

Microcrystalline Quartz (SiO2)

Chert (often called Flint when dark)

Microcrystalline silicon dioxide (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Nephrite Jade

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

Nephrite Jade

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

Nephrite Jade

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

Nephrite Jade

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

Nephrite Jade

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

Raw Corundum (Sapphire/Ruby variant)

Aluminum oxide (Al2O3)

Green Fluorite

Calcium Fluoride (CaF2)

Orange Calcite

Calcium Carbonate (CaCO3)

Rough Green Calcite

Calcite (Calcium Carbonate, CaCO3)

Geode (unopened)

Quartz-filled Geode (SiO2)

Chert (often called Flint in dark varieties)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Limestone with Calcite Veins

Calcium Carbonate (CaCO3)

Chert (Jasper/Flint variant)

Silicon Dioxide (SiO2) - Microcrystalline Quartz