Sedimentary Or Metamorphic (Low Grade)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (specifically Yellow/Honey Jasper variety)

Cryptocrystalline Quartz (SiO2)

Chert (Gravel)

Chert (Cryptocrystalline silicon dioxide, SiO2)

Septarian Nodule (Dragon Stone)

Septarian concretion (composition: Calcium Carbonate / Calcite, Aragonite, and Limestone/Clay)

Chert Pebble (Yellow Jasper)

Microcrystalline Quartz (SiO2)

Graphite

Graphite (C)

Chert (Field-collected variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Porcelain (Stoneware Ceramic)

Mullite / Silica-glass composite (Al6Si2O13)

Yellow Calcite

Calcium Carbonate (CaCO3)

Quartz Crystal Fragment

Silicon Dioxide (SiO2)

Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).

Galena (PbS)

Almandine Garnet

Almandine - Fe3Al2(SiO4)3

Chert (Flint Pebbles)

Microcrystalline quartz (SiO2)

Fluorite (Rainbow Fluorite)

Calcium Fluoride (CaF2)

Crushed Limestone (Gravel)

Calcium Carbonate (CaCO3)

Sandstone (specifically Flagstone)

Arenite (primarily composed of SiO2)

Pyrite

Iron Sulfide (FeS2)

Chrysocolla

Hydrated copper phyllosilicate, Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O)

Geodal Limestone / Calcite Druze

Calcium Carbonate (CaCO3)

Pyrite (on the right) and Magnetite or Hematite (on the left)

Iron Sulfide (FeS2) and Iron Oxide (Fe3O4 or Fe2O3)

Glauconitic Sandstone (Greensand)

Glauconitic Quartz Arenite (containing Glauconite, (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)

Chert (Nodular)

Chert (SiO2 - Microcrystalline Quartz)

Chert (and/or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Druzy Quartz (on Quartzite or Chert)

Silicon Dioxide (SiO2)

Pumice or Scoria

Vesicular volcanic rock

Chert (variant Flint/Novaculite)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Aragonite Star Cluster (or Aragonite Sputnik)

Aragonite (Orthorhombic Calcium Carbonate, CaCO3)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Petrified Wood

Silicified Wood (SiO2)

Halite

Sodium Chloride (NaCl)

Staurolite (Fairy Stone)

Staurolite (formula: Fe2+2Al9Si4O23(OH))

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Pink Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Agate (Chalcedony)

Cryptocrystalline Silica or Silicon Dioxide (SiO2)

Ruby in Kyanite

Corundum in Disthene (Al2SiO5 + Al2O3)

Tumbled Moonstone and Amazonite Chips

Orthoclase (KAlSi3O8) and Microcline (KAlSi3O8) of the Feldspar Group

Druzy Quartz (part of a Geode)

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Pyrite in Quartz

Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)

Moonstone

Orthoclase Feldspar (composed of alternate layers of orthoclase and albite), (K,Na)AlSi3O8

Smoky Quartz

Silicon Dioxide (SiO2)