Sedimentary Or Igneous (Host Environment)

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Fossilized Knightia Fish

Knightia eocaena (set in fossiliferous Micritic Limestone)

Ammonite Fossil in Limestone Matrix

Ammonoidea (subclass) in Calcium Carbonate (CaCO3)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Chert (Jasper/Limonitic Chert)

Microcrystalline Quartz (SiO2)

Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Chert / Quartz Pebble

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartz

Silicon dioxide (SiO2)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Quartz with inclusions (likely Chlorite or Hornblende) and country rock

SiO2 (Quartz) with associated ferromagnesian minerals

Red Siltstone

Siltstone (composed mainly of SiO2 and Fe2O3)

Sandstone

Arenite (SiO2 principal)

River Pebble (Quartz/Jasper)

Silicon Dioxide (SiO2)

Clear Quartz (or Rock Crystal)

Quartz (SiO₂)

Calcite

Calcite (CaCO3)

Red Sandstone

Arenite (Ferruginous Sandstone)

Variscite (or potentially a turquoise/variscite matrix cabochon, or an impression jasper)

AlPO4·2H2O (Variscite) or related phosphate/silicate material depending on exact composition

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Turquoise

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

Serpentinite

Serpentinite ((Mg,Fe,Ni,Al)3Si2O5(OH)4)

Chert (Green variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Chert (Nodule)

Chert (Silicon Dioxide, SiO2)

Chert (Jasper variety)

Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Quartzite river pebble)

Microcrystalline Silica (SiO2)

Chert (and Limestone) River Cobble

Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)

Sandstone (specifically Arkose or Quartz Arenite)

Arenite (primarily SiO2 with possible Feldspar)

Pyrite

Iron Sulfide (FeS2)

Turquoise

CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminum phosphate)

Sandstone (Ferruginous)

Arenite (with Iron Oxides)

Sandstone (Ferruginous)

Sandstone (Clastic sedimentary rock, predominantly SiO2 with Fe2O3 cement)

Sandstone (Cross-bedded Drill Core)

Clastic Sedimentary Rock (primarily SiO2)

Fossiliferous Sandstone (with Brachiopod or Bivalve mold)

Clastic Sedimentary Rock with Macrofossil Mold

Sandstone

Arenite (SiO2 based with quartz grains)

Turquoise

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

Sandstone (likely Graywacke or Arkose variant)

Clastic Sedimentary Rock (SiO2 with assorted lithic fragments)

Diamond (in Matrix)

Carbon (C)

Banded Agate

Cryptocrystalline Silica (SiO2)

Moonstone with Black Tourmaline

Orthoclase (KAlSi3O8) with Schorl inclusions (NaFe3Al6(BO3)3Si6O18(OH)4)

Black Tourmaline

Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Pyritic Sandstone

Clastic Sedimentary Rock (Pyrite-bearing Sandstone)