Mineral Precipitate (Anthropogenic Context)

Andesite Porphyry (Geological Drill Core)

Andesite Porphyry

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic Extrusive)

Sandstone

Arenite (composed primarily of SiO2)

Pyrite

Iron Sulfide (FeS2)

Ruby

Corundum (Aluminium Oxide with Chromium impurities, Al2O3:Cr)

Granite

Granite (felsic intrusive igneous rock)

Fossilized Oyster Shell

Exogyra or Ostrea (Gryphaeidae/Ostreidae family)

Red Sandstone

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 cement)

Red Sandstone

Arenite (primarily Quartz with Hematite cement)

Sandstone with Iron Oxide Staining

Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)

Turquoise (Blue Howlite / Magnesite imitation)

CuAl6(PO4)4(OH)8·4H2O (for natural Turquoise); Ca2B5SiO9(OH)5 (for Howlite)

Red Sandstone

Arenite with iron oxide (Hematite) cement

Sandstone (Quartzose)

Arenite (primarily SiO2)

Red Sandstone

Arenite (with Iron Oxide)

Sandstone (Red Sandstone)

Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide)

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 oxides)

Schist

Schist

Gneiss

Gneiss (High-grade metamorphic rock)

Serpentinite

Serpentinite (composed primarily of serpentine-group minerals like antigorite, chrysotile, and lizardite; chemical formula varies but generally Mg3Si2O5(OH)4)

Fossilized Shark Tooth (Otodus)

Otodus obliquus

Mica Schist with Garnet

Garnet-Mica Schist

Sandstone

Sandstone (Silicon Dioxide, SiO2)

Gold Placer (Gold Flakes and Nuggets)

Native Gold (Au)

Mica Schist with Quartz

Crystalline Schist (SiO2 + KAl2(AlSi3O10)(OH)2)

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Quartz-veined Metamorphic Rock

Quartz Vein in Phyllite or Schist (SiO2 in Silicate Matrix)

Green Aventurine

Silicon Dioxide (SiO2+KAl2(AlSi3O10)(OH)2)

Banded River Rock with Quartz Vein

Siltstone/Greywacke with Quartz (SiO2)

Sandstone with Quartz Vein

Arenite with SiO2 intrusion

Gneiss

Gneiss (High-grade metamorphic rock)

Granite

Granite

River Pebble (Gneiss or Granite)

Metamorphic Rock (likely Gneiss or Granitic composition)

Lepidolite

K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2

Sandstone

Arenite (primarily SiO2)

Sandstone (Graywacke)

Arenite / Graywacke (SiO2 with lithic fragments)

Included Quartz (Garden Quartz / Lodolite)

Quartz (SiO2) with various mineral inclusions

Moss Agate

Silicon Dioxide (SiO2) with mineral inclusions

Moss Agate

Silicon dioxide (SiO2) with mineral inclusions

Beryl (Emerald variety in host rock)

Be3Al2(SiO3)6 (Silicate mineral)