Mineral Precipitate (Anthropogenic Context)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Emerald (Faceted Gemstone)

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Citrine (likely Heat-Treated Amethyst)

Silicon Dioxide (SiO2)

Jasper Beads (Polished)

Silicon Dioxide (SiO2)

Dyed Quartz Geode

Silicon Dioxide (SiO2) with artificial pigment

Fire Opal (in matrix)

Hydrated Silica (SiO2·nH2O)

Opal

Hydrated silica (SiO2·nH2O)

Chalcedony (Common Opal or Agate)

Silicon Dioxide (SiO2)

Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Amethyst

Crystalline Quartz (SiO2) with iron impurities

Botryoidal Chalcedony

Silicon Dioxide (SiO2)

Herkimer Diamond (Quartz)

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily SiO2)

Gold Nugget

Native Gold (Au)

Desert Rose

Gypsum (variety Selenite) or Barite, CaSO4·2H2O

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Quartz (Smoky Quartz variant)

Silicon Dioxide (SiO2)

Amethyst

Quartz (Silicon Dioxide with iron impurities), SiO2

Orange Quartz (Citrine Quartz)

Silicon Dioxide (SiO2) with iron impurities

Citrine Quartz Geode

Silicon Dioxide (SiO2) with iron impurities

Zoisite with Ruby / Anyolite

Anyolite (Ca2Al3(SiO4)3(OH) with Chromian Zoisite and Tschermakite inclusions)

Amethyst (Quartz variety)

Silicon Dioxide (SiO2) with iron impurities

Banded Calcite or Travertine

Calcium Carbonate (CaCO3)

Lepidolite

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

Tiger's Eye

Pseudomorph of Crocidolite (SiO2 with iron oxides)

Sodalite

Sodalite (Na8Al6Si6O24Cl2)

Native Copper (in coinage alloy)

Copper (Cu)

Granite

Granite (Phaneritic Igneous Rock)

Granodiorite / Granite (Weathered)

Granodiorite

Red Sandstone

Arenite (Ferruginous Sandstone)

Garden Quartz (Phantom Quartz)

Silicon Dioxide (SiO2) with various inclusions (often Chlorite, Hematite, or Iron)

Red Sandstone

Arenite with Iron Oxide (Hematite) cement

Jasper containing epidote (Unakite-like)

Epidotized Jasper (SiO2 with Ca2(Al,Fe)3(SiO4)3(OH))

Turquoise

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

Basalt with Quartz/Zeolite Inclusions

Porphyritic Basalt (SiO2 with Aluminosilicates)

Malachite

Copper Carbonate Hydroxide [Cu2CO3(OH)2]

Red Sandstone Pebble

Arenite with Hematite (Fe2O3) cement

Chatoyant Quartz (Cat's Eye Quartz)

Silicon Dioxide (SiO2) with fibrous inclusions of Amphibole or Rutile

Chondrite Meteorite

Ordinary Chondrite (S-type Asteroid fragment)

Portable Ceramic Space Heater

Polished Acrylonitrile Butadiene Styrene (ABS) Plastic with Ceramic Heating Elements

Lepidolite (likely)

K(Li,Al)3(Al,Si)4O10(F,OH)2 (Phyllosilicate mineral, part of the mica group)

Sodalite

Na8(Al6Si6O24)Cl2