Mineral, Jewelry

Amethyst cluster

Amethyst, purple variety of quartz (SiO₂); trigonal crystal system

Amethyst cluster

Amethyst, purple quartz (SiO₂)

Tumbled citrine (possibly heat-treated amethyst)

Quartz, SiO₂; trigonal crystal system

Polished smoky quartz

Quartz (SiO₂), smoky variety

Tumbled amethyst

Quartz, SiO₂; purple color typically from trace iron and natural irradiation

Purple druzy quartz (likely dyed or coated)

Quartz, SiO₂ (trigonal crystal system)

Tumbled amethyst

Quartz, SiO₂; purple coloration from trace iron and natural irradiation

Amethyst (likely tumbled or polished)

Quartz, SiO₂; purple color commonly caused by trace iron and natural irradiation

Yellow Quartz

Silicon Dioxide (SiO2)

Likely marcasite jewelry (metal brooch and earrings)

Marcasite, FeS₂ (often pyrite or marcasite stones set in silver)

Blue Apatite

Calcium phosphate fluorapatite, Ca5(PO4)3(F,Cl,OH)

Malachite pendant

Malachite, Cu₂CO₃(OH)₂

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Petrified Wood

Silicified wood (SiO2)

Yellow Topaz

Al2SiO4(F,OH)2

Turquoise

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

Red bead-and-chain costume jewelry, likely glass or plastic

No geological identification; the red beads appear manufactured and cannot be identified as mineral from the image

Likely garnet gemstone

Garnet-group silicate; species cannot be determined from the photo (common red varieties include almandine, Fe₃Al₂(SiO₄)₃, and pyrope, Mg₃Al₂(SiO₄)₃).

Almandine Garnet

Almandine, Fe3Al2(SiO4)3

Almandine Garnet

Almandine, Fe3Al2(SiO4)3

Faceted transparent gemstone, likely glass or cubic zirconia

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

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.

Polished dendritic agate pendant

Microcrystalline quartz (SiO₂), with dark manganese- or iron-oxide dendrites

Malachite-bearing Rock

Cu2CO3(OH)2

Nephrite Jade

Nephrite

Red cabochon gemstone, likely garnet

Likely almandine garnet, Fe₃Al₂(SiO₄)₃; identification from the image is uncertain

Tourmaline

Complex boron silicate, (Na,Ca)(Al,Fe,Li)_3Al_6(BO_3)_3Si_6O_18(OH)_4

Pale green stone, possibly serpentine

Serpentinite (dominantly serpentine-group minerals; visual identification is uncertain)

Polished garnet cabochon (likely almandine)

Almandine garnet, Fe₃Al₂(SiO₄)₃ (tentative identification)

Shark Tooth Fossil

Vertebrate fossilized tooth (various genera such as Carcharodon, Otodus, or Negaprion)

Small stud earring with a purple gemstone (possibly amethyst)

Possible amethyst, a purple variety of quartz (SiO₂); identification is uncertain from the image

Green cabochon gemstone pendant, likely turquoise or dyed green turquoise

Probably turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O; exact identification requires testing

Ruby (in costume jewelry context)

Corundum (Al2O3) with Chromium impurities

Cut red gemstone, likely ruby

Ruby, gem-quality corundum (Al₂O₃) colored by chromium

Malachite with Quartz

Cu2CO3(OH)2 / SiO2

Tumbled Mixed Gemstones and Rocks

Various mineral species including quartz (SiO2) and silicate minerals

Turquoise

Turquoise, CuAl6(PO4)4(OH)8·4H2O

Pink Tourmaline

Elbaite (Na(LiAl)3Al6(BO3)3Si6O18(OH)4)

Green Quartz

Silicon Dioxide (SiO2)

Green Quartz

Silicon Dioxide (SiO2)

Yellow Quartz

Silicon Dioxide (SiO2)

Jasper

Microcrystalline quartz (SiO2)