Synthetic (Man Made Glass)

Blue glassy gemstone cabochon, likely dyed chalcedony or glass

Uncertain; possible dyed chalcedony (microcrystalline quartz, SiO₂)

Goldstone

Aventurine Glass (SiO2 + Cu small inclusions)

Faceted Gemstone

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

Blue Goldstone

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

Green sea glass or tumbled green quartz (uncertain)

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

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Exposed Aggregate Concrete (Pea Gravel)

Concrete with Siliceous Alluvial Gravels

Moldavite

Tektite (Impact Glass), ~80% SiO2 + Al2O3

Tumbled gray stone, likely quartz-rich pebble

Probable microcrystalline quartz/chalcedony (SiO₂), possibly gray jasper or quartzite

Blue-stone and diamond ring

Blue stone is possibly blue sapphire (corundum, Al₂O₃); surrounding stones appear to be diamonds (carbon, C).

Blue Obsidian (Cullet Glass)

Silicon Dioxide (Amorphous Glass)

Likely clear quartz pebble or glassy quartz fragment

Quartz (silicon dioxide, SiO₂)

Green sea glass (likely bottle glass)

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

Black glassy fragment, likely obsidian or industrial glass

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

Concrete Fragment

Hardened Portland cement and mineral aggregate

Heart-shaped faceted gemstone pendant

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

Decorative mosaic cross containing mixed rock and glass fragments

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

Rock crystal (clear quartz), possibly cloudy quartz

Quartz, silicon dioxide (SiO₂)

Asphalt Concrete

Bituminous conglomerate

Slag (Industrial Byproduct)

Artificial silicate/iron byproduct

Green glass sphere/marble

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

Goldstone beads (likely brown goldstone)

Man-made copper-bearing glass; not a natural mineral. Often sold as “aventurine glass.”

Diamond (or Cubic Zirconia simulant)

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

Sea Glass

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

Polished labradorite sphere

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

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)

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)

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

Polished white chalcedony or quartz pendant

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

Goldstone (likely blue-free synthetic goldstone pendant)

Synthetic aventurine glass; silica glass with dispersed metallic copper crystals

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂), likely milky quartz

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

Blue obsidian-like volcanic glass

Volcanic glass, chiefly silica-rich amorphous material (composition uncertain)

Milky quartz (likely quartz crystal fragment)

Quartz, silicon dioxide (SiO₂)

Blue opalite (often sold as synthetic opal)

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

Green sea glass (likely bottle glass)

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

Chipped Glass/Plastic Fragment

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

Synthetic Costume Accessory (Non-Geological)

Polyester and Acrylic Fiber (Anthropogenic polymer)

Rock crystal quartz fragments

Quartz (silicon dioxide, SiO₂)

Likely iron-rich slag or weathered ironstone fragment

Uncertain; possibly iron oxide–rich material (hematite/goethite) or industrial iron slag

Asphalt (Road Aggregate)

Bituminous conglomerate