Sedimentary (Microcrystalline Silicate)

Polished orbicular jasper (likely ocean jasper)

Microcrystalline quartz (SiO₂) with iron oxides and accessory minerals

Jasper with Epidote Vein

Silicon Dioxide (SiO2) with Calcium Aluminum Iron Silicate (Ca2(Al,Fe)3(SiO4)3(OH))

Green Aventurine (or Xiuyan Jade / Serpentine)

Silicon Dioxide (SiO2) with Fuchsite inclusions or Magnesium Silicate

Shale (with Iron Staining)

Argillaceous mudstone / Shale

Common Green Opal

Hydrated amorphous silicon dioxide (SiO2·nH2O)

Ferrous Slag

Fused calcium-iron silicates (Industrial Slag)

Granitic Gneiss

Gneiss (Complex silicate composition)

Banded Gneiss

Gneiss (complex metamorphic silicate rock)

Polished banded iron formation (BIF)

Banded iron formation; chiefly hematite/magnetite and microcrystalline quartz (chert), with iron silicates

Glauconitic Sandstone

Glauconitic Quartz Arenite (with K,Mg,Fe,Al silicate hydroxide)

Light-colored limestone (probable fossiliferous or micritic limestone)

Calcite-rich carbonate rock; predominantly CaCO₃ (calcite)

Glauconitic Sandstone

Glauconitic Quartz Arenite

Green Sandstone

Glauconitic Sandstone

Siltstone or Sandstone Pebble

Lithic Arenite / Quartzose Siltstone

Sandstone

Arenite (primarily SiO2)

Tumbled jasper pebble

Jasper, an opaque microcrystalline variety of quartz (SiO₂), commonly containing iron oxides and other silicates

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Glauconitic Sandstone

Glauconitic Sandstone (Quartz with Glauconite)

Jadeite Jade

Jadeite (Sodium Aluminum Silicate, NaAlSi₂O₆)

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, SiO2)

Puddingstone (Quartzite Pebble)

Metaconglomerate / Jasper-Quartzite Pebble

Limonite (Ironstone Concretion)

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

Coal

Bituminous Coal (organic sedimentary rock)

Bauxite

Bauxite (Al2O3·2H2O)

Bauxite

Bauxite (Al2O3·nH2O)

Kaolinite (Chalky Clay)

Kaolinite (Al2Si2O5(OH)4)

Bauxite

Alumina-rich rock (consisting of Gibbsite, Boehmite, and Diaspore)

Sandstone

Arenite (primarily SiO2)

Calcite-rich limestone

Limestone, primarily calcite (CaCO₃), possibly fossiliferous or dolomitic

Aragonite (Banded Calcite / 'Mexican Onyx')

Aragonite (Calcium Carbonate - CaCO3)

Man-made Polished Porcelain Tile (Artificial Geologic Lookalike)

Fused Silicate Ceramic with Alumina (Synthetic Kaolinite derivative)

Chrysocolla in Jasper (Chryso-Jasper)

Cu2-xAlx(H2-xSi2O5)(OH)4·n H2O (Chrysocolla) + SiO2 (Jasper)

Polished ocean jasper (orbicular jasper)

Microcrystalline quartz (SiO₂) with chalcedony, iron oxides, and assorted silicate inclusions

Coal (Anthracite/Bituminous)

Carbo fossilium (primarily Carbon)

Yellow Jade (often Serpentine or Dolomite)

Primarily Serpentine (Mg3Si2O5(OH)4) or Dolomite (CaMg(CO3)2), though the term 'yellow jade' is also sometimes applied to varieties of true nephrite or jadeite.

Rounded river pebble, likely weathered limestone or sandstone

Indeterminate carbonate or siliciclastic sedimentary rock; likely limestone (calcite-rich, CaCO₃) or lithic sandstone

Orange tumbled stone, likely carnelian

Carnelian: orange-red microcrystalline quartz, SiO₂ (chalcedony)

Sandstone (Glauconitic)

Glauconitic Quartz Sandstone (SiO2 + (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Sandstone

Arenite

Sandstone (Ferruginous)

Arenite with Iron oxide staining (SiO2 with Fe2O3)

Bauxite

Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))

Sandstone (Banded)

Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide staining)