Man Made Rock (Technosol)

Geode (Chert or Quartz Nodule)

Silicon Dioxide (SiO2)

Druzy Quartz (on Chalcedony/Agate base)

Silicon Dioxide (SiO2)

Pumice

Pumice (Vesicular volcanic glass / Rhyolite or Trachyte)

Schist

Mica Schist

Chert (Nodule)

Silicon dioxide (SiO2) - Cryptocrystalline Quartz

Quartzite

Quartzite (primarily SiO2)

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Quartzite

Quartzite (primarily SiO₂)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)

Chert (Jasper/Flint variation)

Chert (SiO2)

Amethyst on Agate/Basalt Matrix

Silicon Dioxide (SiO2) with iron impurities

Sandstone (Greywacke/Siltstone variant)

Clastic Sedimentary Rock (Lithic Wacke)

Quartzite (River Pebble)

Metamorphosed Quartz Sandstone (SiO2)

Quartz Pebble

Quartz (Silicon Dioxide - SiO2)

Crinoid Fossil in Limestone

Class Crinoidea in Carbonate Matrix (CaCO3)

Emerald with Matrix (Emerald in Mica Schist)

Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities

Hag Stone

Siltstone or Fine-grained Sandstone with boring (e.g., Lithophaga impact)

Chert (White Chert/Flint)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

Limonite (Iron Ore)

Limonite; FeO(OH)·nH2O

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Amygdaloidal Basalt

Amygdaloidal Basalt with Secondary Infilling (e.g., Agate, Quartz, or Zeolite)

Turquoise

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

Calcite (Yellow/Orange variety - sometimes called Honey Calcite)

Calcite

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz Vein with Iron Staining

Silicon Dioxide (SiO2) with limonite/hematite staining

Green Moonstone (Garnierite)

Nickel-bearing Magnesium Silicate (often a mix of Serpentine and Talc/Chlorite groups)

Diamond

Diamond (Pure Carbon, C)

Almandine Garnet

Almandine (Fe3Al2Si3O12)

Copper Ore with Chrysocolla and Azurite

Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla) / Cu3(CO3)2(OH)2 (Azurite)

Septarian Nodule

Septarian Nodule (Mixture of Calcite, Aragonite, and Limestone/Clay)

Petrified Wood

Silicified Wood (SiO2)

Sandstone (Quartzose Sandstone)

Arenite (SiO2)

Chert (White-Tan variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Agate

Silicon dioxide (SiO2)

Serpentinite

Serpentinite (complex of Antigorite, Lizardite, and Chrysotile, Mg3Si2O5(OH)4)

Quartzite (River Cobble)

Quartzite (predominantly SiO2)

Fossil Shell Fragment (possibly Brachiopod or Bivalve)

Calcium Carbonate (CaCO3) - Phylum Brachiopoda or Mollusca

Greenschist with Quartz Veining

Greenschist (commonly containing Chlorite, Actinolite, and Epidote)

Sandstone

Arenite (primarily SiO2 - Silicon Dioxide)

Metagabbro / Epidote Gneiss

Epidote bearing Hornblende Gneiss

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)