Sedimentary (Chemically Precipitated) Or Metamorphic

Quartzite

Quartzite (primarily SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

White Chalcedony (Agate)

Silicon Dioxide (SiO2)

Tiger Iron

Tiger Iron (Hematite, Red Jasper, and Chert/Tiger's Eye composite)

Pyrite

Iron Pyrite (FeS₂)

Banded Calcite (often sold as Mexican Onyx or Aragonite)

Calcite/Aragonite (Calcium Carbonate, CaCO3)

Chert (often called Flint or Jasper)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

Chert (specifically Pink Chert or Jasperized Chert)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Chert (variations include Flint or Jasper)

Silicon Dioxide (SiO2)

Chert (often called Flint in this variation)

Silicon dioxide (SiO2) - Microcrystalline quartz

Chert (specifically Flint or Jasper variant)

Microcrystalline silica (SiO2)

Chert (Jasper/Chalcedony variety)

Silicon Dioxide (SiO2)

Amygdaloidal Basalt

Basalt with secondary mineral infilling (commonly Zeolite, Calcite, or Quartz)

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic volcanic rock including secondary mineral infills)

Quartz (likely milky quartz or a stained variety)

Silicon Dioxide (SiO₂)

Calcite

Calcite (CaCO₃, Calcium Carbonate)

Pyrite

Pyrite (FeS2)

Azurite Malachite (Mixed)

Azurite-Malachite; Azurite: Cu3(CO3)2(OH)2 / Malachite: Cu2CO3(OH)2

Chert (Field Stone/Pebble)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Chalcedony)

Microcrystalline Quartz (SiO2)

Aragonite

Aragonite (CaCO3)

Carnelian

SiO2 (Chalcedony with iron oxide impurities)

Fluorite

Calcium Fluoride (CaF2)

Selenite (Satin Spar)

Gypsum (CaSO4·2H2O)

Chert (Iron-Stained)

Microcrystalline Quartz (SiO2)

Coquina

Bioclastic Limestone (CaCO3)

Banded Calcite (often sold as Mexican Onyx)

Calcium Carbonate (CaCO3)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Chert (River Pebble)

Microcrystalline silicon dioxide (SiO2)

Chert (Nodular Chert)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (with small quartz inclusion)

Microcrystalline Silica (SiO2)

Quartz / Quartzite Fragment

Silicon Dioxide (SiO2)

Azurite in Gossan

Azurite (Cu3(CO3)2(OH)2) in Limonite/Goethite matrix

Howlite

Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)

Green Banded Agate

Agate (Cryptocrystalline variety of Quartz, SiO2)

Magnetite / Iron Ore

Magnetite (Fe3O4)

Quartzite (Water-worn Pebble)

Metamorphosed Quartz Sandstone (SiO2)

Quartzite

Quartzite (primarily Silicon Dioxide, SiO2)

Yellow Quartzite (River Pebble)

Quartzite (primarily Silicon Dioxide, SiO2)

Chert (River Cobble)

Microcrystalline or cryptocrystalline Quartz (SiO2)