Synthetic Glass (Man Made)

Blue Goldstone

Man-made glass with suspended copper, cobalt, or manganese particles

Blue Obsidian (Cullet Glass)

Silicon Dioxide (Amorphous Glass)

Concrete Fragment

Hardened Portland cement and mineral aggregate

Diamond (or Cubic Zirconia simulant)

Carbon (C) - Diamond / Zirconium dioxide (ZrO2) - CZ

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Green sea glass or tumbled green quartz (uncertain)

Likely quartz (SiO₂) if natural; alternatively man-made soda-lime glass

Faceted Gemstone

Unknown transparent mineral, possibly Diamond (C), Cubic Zirconia (ZrO2), Quartz (SiO2), or Glass

Decorative mosaic cross containing mixed rock and glass fragments

Polychrome aggregate; likely quartz, feldspar, marble, granite, and assorted colored glass

Asphalt Concrete

Bituminous conglomerate

Slag (Industrial Byproduct)

Artificial silicate/iron byproduct

Black glassy fragment, likely obsidian or industrial glass

Volcanic glass (obsidian), chiefly amorphous SiO₂; identification uncertain from image

Heart-shaped faceted gemstone pendant

Likely yellow quartz (citrine) or synthetic yellow stone, set in metal with small clear accent stones

Green glass sphere/marble

Soda-lime glass (primarily SiO2, Na2O, CaO)

Green sea glass (likely bottle glass)

Man-made soda–lime silicate glass; not a natural mineral

Rock crystal (clear quartz), possibly cloudy quartz

Quartz, silicon dioxide (SiO₂)

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)

Transit Token (RTD Denver)

Nickel-plated brass or bronze alloy (Cu-Sn-Zn-Ni)

Polished white chalcedony or quartz pendant

Microcrystalline quartz (chalcedony), SiO₂; exact identification is uncertain from the image

Polished labradorite sphere

Labradorite, calcic plagioclase feldspar ((Ca,Na)(Al,Si)₄O₈)

Asphalt (Road Aggregate)

Bituminous conglomerate

Small greenish crystal/mineral fragment

Indeterminate; possibly olivine, quartz, or a green gemstone fragment

Pyrite in Quartz (Drill Core)

Silicon Dioxide (SiO2) with Iron Sulfide (FeS2) inclusions

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂), likely milky quartz

Sea Glass

Amorphous silicon dioxide (SiO2) - Man-made glass tumbled by nature

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)

Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)

Mystic Topaz (Treated Quartz or Topaz)

Aluminum silicate fluoride hydroxide [Al2SiO4(F,OH)2] with thin-film metallic coating

Sandstone Concretion

Limonitic Sandstone Concretion

Rock crystal quartz fragments

Quartz (silicon dioxide, SiO₂)

Crushed Stone (Likely Limestone or Granite)

Calcium Carbonate (CaCO3) for Limestone / Quartz and Feldspar for Granite

Milky quartz (likely quartz crystal fragment)

Quartz, silicon dioxide (SiO₂)

White cabochon gemstone, likely milky chalcedony or opalite

Chalcedony: microcrystalline quartz, SiO₂; appearance may also indicate synthetic opalite glass

Blue opalite (often sold as synthetic opal)

Opalite glass; amorphous hydrated silica if natural opal (SiO₂·nH₂O)

Green obsidian (likely molded or heat-treated glass-like specimen)

Volcanic glass; predominantly rhyolitic composition (silica-rich amorphous SiO₂)

Ferrous Slag

Iron/Steel Slag (Complex Calcium-Alumino-Silicates)

Synthetic Costume Accessory (Non-Geological)

Polyester and Acrylic Fiber (Anthropogenic polymer)

Aura Quartz (Rainbow Quartz)

Silicon Dioxide (SiO2) with metallic vapor coatings

Chipped Glass/Plastic Fragment

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

Polished labradorite pendant

Labradorite, a calcium-rich plagioclase feldspar (approximately NaAlSi₃O₈–CaAl₂Si₂O₈)

Citrine Quartz

Citrine (Silicon Dioxide, SiO2)

Unidentifiable Rock Fragment

Asphalt Concrete (Bituminous Conglomerate)

Anthropogenic Bituminous Conglomerate

Green sea glass (likely bottle glass)

Man-made soda-lime silicate glass; not a natural mineral