Metal (Elemental Mineral)

Quartz Vein on Matrix

Silicon Dioxide (SiO2)

Ferruginous Sandstone

Sandstone with Iron Oxide (Limonite/Goethite)

Polished orange chalcedony pendant

Chalcedony, microcrystalline quartz (SiO₂), likely orange carnelian or orange agate

Ruby (mounted cabochon)

Corundum, Al₂O₃; red color typically from chromium

Quartz-rich pegmatite with mica

Granitic pegmatite; chiefly quartz (SiO₂), feldspar, and muscovite/biotite mica

Green faceted gemstone earrings, likely synthetic emerald-colored glass or cubic zirconia

Undetermined; possible glass (amorphous silicate) or synthetic cubic zirconia (ZrO₂)

Blue slag glass / industrial glass fragment

Artificial silicate glass, composition variable; likely copper- or cobalt-colored furnace slag

Granite

Felsic intrusive igneous rock

Cubic Zirconia (Jewelry Setting)

Zirconium Dioxide (ZrO2)

Merlinite (dendritic opal)

Common opal (hydrated amorphous silica, SiO₂·nH₂O) with dark manganese-oxide dendrites; the trade name “merlinite” is also applied to other patterned stones.

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix

Amethyst cabochon jewelry

Amethyst, purple variety of quartz (SiO₂)

Granite

Intrusive Igneous Rock

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Pyrite

Iron Sulfide (FeS2)

Amethyst (in jewelry)

Silicon Dioxide (SiO2) with iron impurities

Man-made Slag (Industrial Byproduct)

Anthropogenic Glassy Residue

Amethyst cabochon ring

Amethyst, purple quartz (SiO₂), colored primarily by iron-related defects and irradiation

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Ruby (set in a ring; possibly synthetic or imitation)

Corundum, Al₂O₃; red color is typically caused by chromium

Native silver fragment (probable)

Silver, Ag; possibly silver-bearing sulfide or plated metal

Quartz-rich metallic sulfide ore (probable pyrite-bearing rock)

Pyrite, FeS₂, in a quartz-rich host; exact identification is uncertain from the image

Granite

Felsic intrusive igneous rock

Quartz-bearing pyrite–chalcopyrite specimen

Pyrite (FeS₂), likely chalcopyrite (CuFeS₂), with quartz (SiO₂)

Bauxite

Bauxite (mixture including Gibbsite Al(OH)3, Boehmite γ-AlO(OH), and Diaspore α-AlO(OH))

Granite

Intrusive Igneous Rock

Gold-Bearing Quartz Ore

Crystalline Silicon Dioxide (SiO2) with Trace Aurum (Au)

Faceted transparent gemstone, likely glass or cubic zirconia

Uncertain from image; possible cubic zirconia (zirconium dioxide, ZrO₂) or glass imitation

Iridescent bismuth crystal

Bismuth (Bi), commonly laboratory-grown and oxidized

Copper Ore

Native Copper (Cu) often found with Chalcocite (Cu2S) or Bornite (Cu5FeS4)

Aura Quartz

Silicon Dioxide (SiO2) with Titanium/Metal vapor coating

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Gossan (Iron Cap)

Limonitic Gossan (Fe2O3·nH2O mixed)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Beryl (Aquamarine)

Be3Al2Si6O18

Gossan (Iron Hat)

Hydrous Iron Oxides (predominantly Goethite FeO(OH) and Limonite)

Native Copper

Native Copper (Cu)

Granite

Felsic intrusive igneous rock

Red Sandstone

Quartz Arenite (with Iron Oxide)

Vanadinite

Vanadinite (Pb5(VO4)3Cl)

Pink Lepidolite

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

Gossan (Limonite/Goethite)

Hydrated iron oxides (primarily FeO(OH)·nH2O)