Sedimentary (Fossilized Organic Remain)

Orange Calcite (Mexican Onyx)

Calcium Carbonate (CaCO3)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Pyrite in Matrix (often with Chalcopyrite)

Iron Sulfide (FeS2) / Copper Iron Sulfide (CuFeS2)

Howlite

Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)

Optical Calcite (Iceland Spar)

Calcite (Calcium Carbonate, CaCO3)

Gneiss

Gneiss (High-grade metamorphic rock)

Onyx Marble (Banded Calcite)

Calcite (Calcium Carbonate, CaCO3)

Barite

Barium Sulfate (BaSO4)

Potassium Feldspar and Quartz

KAlSi3O8 (Potassium Feldspar) and SiO2 (Quartz)

Chalcedony (Agate/Quartz)

Silicon Dioxide (SiO2)

Blue Chalcedony

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Mixed collection of minerals and rocks (Jasper, Carnelian, Granite, and Quartz)

Silicon Dioxide (SiO2) with varying impurities for silicates and igneous aggregates

Blue Chalcedony

Silicon Dioxide (SiO2)

Carnelian and White Quartz Bracelet

Silicon Dioxide (SiO2) - specifically Carnelian (Chalcedony) and Rock Crystal/Snow Quartz

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Optical Calcite (Iceland Spar)

Calcite (Calcium Carbonate, CaCO3)

Quartz

Silicon dioxide (SiO2)

Manganese Oxide Crust on Limestone

Manganese Oxides (e.g., Pyrolusite MnO2 or Romanechite) on CaCO3

Dendritic Agate or Tree Agate

Silicon Dioxide (SiO2) with impurities of manganese or iron oxide

Banded Sandstone (Wonderstone)

Sandstone with Liesegang Rings (SiO2 with Iron Oxides)

Chert (Hagstone/Gasket Rock variant)

Chert (SiO2)

Ferruginous Sandstone

Arenite with Iron-oxide cement (composed of Quartz and Limonite/Hematite)

Chert (Flint)

Microcrystalline quartz (SiO2)

Jasper with Quartz Veining

Silicon Dioxide (SiO2) with impurities such as Fe2O3

Jasper or Agate-bearing Chert

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Yellow Jasper

Chalcedony (SiO2) with goethite or limonite inclusions

Turquoise

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

Sandstone (with Limonite staining)

Arenite (FeOx-rich)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Sandstone

Arenite (primarily SiO2 with various cementing agents)

Sandstone (likely Graywacke or Lithic Sandstone)

Arenite / Wacke (SiO2 based with lithic fragments)

Sandstone (Quartzose)

Arenite (SiO2 principal)

Sandstone (Quartzite-rich Pebble)

Arenite (composed primarily of SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide cement)

Limestone

Calcium Carbonate (CaCO3)

Limestone

Calcium Carbonate (CaCO3)

Sandstone

Arenite (primarily SiO2)

Limestone

Calcium Carbonate (CaCO3)

Red Sandstone (Iron-Rich)

Arenite (Fe2O3)

Sandstone (Ferruginous)

Arenite (Fe-rich SiO2)

Sandstone (River Cobble)

Arenite

Limestone

CaCO3 (principally composed of Calcite)