Sedimentary (Secondary Classification For A Weathered Mineral Specimen)

Quartz (Common Quartz Pebble)

Silicon Dioxide (SiO2)

Geode with Quartz/Chalcedony

Silicon Dioxide (SiO2)

Turquoise

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

Quartz on Sandstone

Silicon Dioxide (SiO2) in Lithic Sandstone

Specular Hematite

Hematite (Fe2O3)

Sandstone with Algae Growth

Arenite with Chlorophyta/Lichen

Limonite (Iron Ore)

Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Sandstone (Weathered)

Arenite (primarily SiO2)

Erythrite (or Lab-Grown Cobaltite/Cinnabar Analog)

Erythrite (Co3(AsO4)2·8H2O)

Limonite/Goethite Nodule

Iron Oxyhydroxide (primarily FeO(OH)·nH2O)

Sandstone (Quartz Arenite)

Sandstone (SiO2 with possible mineral cements)

Mica Schist with Iron Staining

Muscovite/Biotite Schist

Turquoise (possible Dyed Howlite or Magnesite imitation)

CuAl6(PO4)4(OH)8·4H2O (Turquoise)

Limonite (Iron Ore)

Limonite (Hydrous ferric oxides), generic formula FeO(OH)·nH2O

Agate Nodule / Weathered Chert

SiO2 (Silicon Dioxide - Microcrystalline Quartz)

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Turquoise

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

Limonite and Goethite on Gossan

FeO(OH)·nH2O

Turquoise

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

Chert Nodule (Fossiliferous Chert)

Microcrystalline Quartz (SiO2)

Limonite-pseudomorph after Pyrite (Prophecy Stone)

Goethite and Limonite secondary minerals (FeO(OH)·nH2O) replacing Pyrite (FeS2)

Yellow Chalcedony (Agate Pebble)

Silicon Dioxide (SiO2)

Turquoise (Rough Specimens)

Hydrous phosphate of copper and aluminium - CuAl6(PO4)4(OH)8·4H2O

Limonite (Iron Ore)

Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O)

Yellow Ochre / Limonite

Limonite (Hydrated Iron(III) Oxide-Hydroxide, FeO(OH)·nH2O)

Quartz Geode (River Cobble)

Silicon Dioxide (SiO2)

Vanadinite

Vanadinite (Pb5(VO4)3Cl)

Sandstone (Weathered Pebble)

Arenite (primarily SiO2)

Pink Chalcedony (Agate/Jasper blend)

Silicon Dioxide (SiO₂)

Limonite (Ironstone Concretion)

Limonite (Hydrous ferric oxide mixture, FeO(OH)·nH2O)

Specular Hematite with Quartz and Limonite

Hematite (Fe2O3) with Quartz (SiO2) and Limonite (FeO(OH)·nH2O)

Sandstone (Weathered Pebble)

Arenite (composed primarily of SiO2)

Ironstone Concretion / Goethite-Hematite Nodule

Goethite/Hematite (α-FeO(OH) / Fe2O3)

Quartz (Milky or Clear variety)

Silicon Dioxide (SiO2)

Chalcedony (Agate)

Silicon Dioxide (SiO2)

Limonite (Ironstone Concretion)

Limonite (Hydrated iron(III) oxide-hydroxide, mixtures of FeO(OH)·nH2O)

Limonite (Iron Ore)

Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)

Sandstone (likely Calcareous or Quartz-rich)

Arenite (SiO2 based typically)

Turquoise

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

Turquoise

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