Mineral (Extraterrestrial)

Limonite (Ironstone Concretion)

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

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Sandstone with Iron Oxide Staining

Arenite with Limonite/Hematite alteration

Ironstone Concretion

Siderite or Hematite Concretion

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Desert Rose (Sand Barite/Gypsum Rose)

Barium Sulfate (BaSO4) or Hydrated Calcium Sulfate (CaSO4·2H2O)

Red Sandstone

Arenite (primarily SiO2 with Fe2O3)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Turquoise

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

Red Sandstone

Arenite (primarily Quartz, SiO2, with Iron Oxide cementing agent)

Dendritic Agate

Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides

Turquoise

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

Fossilized Bone Fragment

Permineralized Vertebrate Bone (Hydrox yapatite replaced by Silica or Calcite)

Ironstone (with Limonite/Goethite)

Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O and Hematite Fe2O3)

Azurite and Malachite on Matrix

Azurite: Cu3(CO3)2(OH)2; Malachite: Cu2CO3(OH)2

Brown Sandstone

Arenite (primarily Quartz and Feldspar, with Iron Oxide cement)

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Botryoidal Goethite

Goethite (α-Fe3+O(OH))

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Quartz Geode

Crystalline Silicon Dioxide (SiO2) within a nodule

Goethite pseudomorph after Pyrite

Goethite (FeO(OH)) pseudomorph after Pyrite (FeS2)

Amethyst

Silicon dioxide (SiO2) with iron impurities

Sunstone

Oligoclase (Plagioclase Feldspar), (Na,Ca)(Si,Al)4O8

Fire Opal in Host Rock

Amorphous Hydrous Silica (SiO2·nH2O)

Desert Rose (Gypsum/Baryte)

Hydrated Calcium Sulfate (CaSO4·2H2O)

Quartz Geode with Goethite/Hematite

Silicon Dioxide (SiO2) with Iron Oxides

Malachite with Chrysocolla

Copper carbonate hydroxide (Cu2CO3(OH)2) and Hydrated copper silicate (Cu,Al)2H2Si2O5(OH)4·nH2O

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)

Smoky Quartz (Herkimer-style)

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Geode (Unopened)

Silica-rich Concretion (primarily SiO2)

Fossilized Shark Tooth (Otodus obliquus)

Otodus obliquus (Mineral: Fluorapatite)

River Pebble (likely Quartzite or Basalt)

Quartzite (SiO2 as primary mineral)

Abalone Shell (Nacre)

Aragonite (CaCO3) - Biogenic Mineral

Quartzite

Quartzite (Primary mineral: SiO2)

Quartzite

Quartzite (Primary mineral: SiO2)

Quartzite

Quartzite (Primary mineral: SiO2)

Quartzite

Quartzite (Primary mineral: SiO2)

Quartzite

Quartzite (Primary mineral: SiO2)