Mineraloid (Human Made Geological Specimen)

Green Opal or Yellow Opal

Hydrated Silica (SiO2·nH2O)

Green cabochon, likely dyed or imitation material

Undetermined; the image is insufficient to identify a mineral species

Dyed red crystal aggregate, likely quartz or salt

Uncertain; possibly dyed quartz (SiO₂) or halite (NaCl)

Iron-rich slag or ironstone; appearance is not diagnostic

Likely iron-oxide-rich material (hematite, Fe₂O₃, and/or magnetite, Fe₃O₄); possibly smelting slag

Tumbled quartz bead bracelet

Quartz (SiO₂), likely milky or rose quartz

Dyed, polished stone—possibly rhodonite or pink jasper

Likely rhodonite (MnSiO₃) or manganese-rich jasper; exact identification requires testing

Brown chert (flint)

Microcrystalline quartz (SiO₂), varieties called chert or flint

Tumbled purple gemstone, likely amethyst

Amethyst, purple variety of quartz (SiO₂)

Quartzite

Metamorphic Quartzite (SiO2)

Tumbled translucent quartz or chalcedony fragment

Silicon dioxide, SiO₂; likely quartz/chalcedony

Tumbled quartz (likely clear quartz)

Quartz, silicon dioxide (SiO₂)

Polished greenstone (likely serpentinite or green granite)

Probably serpentinized ultramafic rock, chiefly serpentine-group minerals; exact identification requires testing

Tumbled yellow chalcedony (likely yellow jasper or silicified material)

Microcrystalline quartz, SiO₂; precise identification requires testing

Polished green stone, likely serpentine or nephrite jade

Serpentine-group minerals (commonly antigorite/lizardite) or nephrite, a fibrous tremolite–actinolite aggregate

Blue-beaded gemstone jewelry, likely lapis lazuli or dyed blue agate

Uncertain from the image; possible lazurite-bearing lapis lazuli (Na₃Ca(Si₃Al₃)O₁₂S) or blue chalcedony (SiO₂)

Obsidian (Blue)

Volcanic Glass (SiO2)

Tumbled quartz (likely milky/rose quartz)

Quartz, silicon dioxide (SiO₂)

Tumbled rose quartz

Quartz, silicon dioxide (SiO₂), pink variety

Likely yellow quartz gemstone ring

Quartz (SiO₂), possibly heat-treated citrine or lemon quartz; metal setting appears to be brass/gold-colored alloy

Tiger’s eye beads

Tiger’s eye (quartz variety), SiO₂, with pseudomorphic fibrous crocidolite/goethite inclusions

Chipped Glass/Plastic Fragment

Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic

Obsidian

Volcanic glass (SiO2 + impurities)

Tumbled orange calcite

Calcite (CaCO₃)

Likely clear quartz pebble or glassy quartz fragment

Quartz (silicon dioxide, SiO₂)

Polished hematite (specimen identification uncertain)

Hematite, α-Fe₂O₃

Flint / Chert Pebble

Microcrystalline Quartz (SiO2)

Chert (Flint / Jasper variant)

Microcrystalline Quartz (SiO2)

Tektite (Indochinite)

Tektite (SiO2 + Al2O3)

Chert / Flint

Silicon dioxide (SiO2)

Industrial Slag

Anthropogenic Vitreous Slag

Polished quartz crystal point

Quartz (silicon dioxide, SiO₂)

Blue-green slag glass or chalcedony-like material

Likely industrial glassy slag; exact identification requires testing

Quartzite (Lithic Artifact)

Quartzite (SiO2)

Black Obsidian

Volcanic Glass (SiO2 + impurities)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Common Opal

SiO2·nH2O

Common Opal

SiO2·nH2O (Hydrated Silicon Dioxide)

Polished hematite

Hematite, iron(III) oxide (α-Fe₂O₃)

Polished druzy quartz specimen

Quartz (SiO₂), likely druzy quartz with possible blue chalcedony or inclusions

Tumbled green aventurine (likely)

Quartz (SiO₂) with fuchsite or other mica inclusions

Pearl

Calcium Carbonate (Aragonite) with Conchiolin; formula: CaCO3

Polished orbicular granite (likely orbicular diorite)

Orbicular granitoid; chiefly quartz, feldspar, and dark amphibole/biotite