Synthetic (Man Made Glass)

Black glassy fragment, likely obsidian or industrial glass

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

Green glass sphere/marble

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

Green Aventurine

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

Polished white chalcedony or quartz pendant

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

Rock crystal (clear quartz), possibly cloudy quartz

Quartz, silicon dioxide (SiO₂)

Transit Token (RTD Denver)

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

White cabochon gemstone, likely milky chalcedony or opalite

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

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

Asphalt (Road Aggregate)

Bituminous conglomerate

Blue opalite (often sold as synthetic opal)

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

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂), likely milky quartz

Polished labradorite sphere

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

Rock crystal quartz fragments

Quartz (silicon dioxide, SiO₂)

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

Green sea glass (likely bottle glass)

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

Synthetic Costume Accessory (Non-Geological)

Polyester and Acrylic Fiber (Anthropogenic polymer)

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

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

Crushed Stone (Likely Limestone or Granite)

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

Ferrous Slag

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

Sea Glass

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

Chipped Glass/Plastic Fragment

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

Aura Quartz (Rainbow Quartz)

Silicon Dioxide (SiO2) with metallic vapor coatings

Green cabochon gemstone, likely aventurine or dyed chalcedony

Indeterminate from image; possible quartz variety (SiO₂), including aventurine quartz or chalcedony

Milky quartz (likely quartz crystal fragment)

Quartz, silicon dioxide (SiO₂)

Orgonite Pyramid (containing Amethyst and mixed minerals)

Silicon Dioxide (SiO2) in synthetic resin

Concrete Rubble with Aggregate

Hardened Portland Cement Paste with Coarse Aggregate

Unidentifiable Rock Fragment

Asphalt Concrete (Bituminous Conglomerate)

Anthropogenic Bituminous Conglomerate

Concrete

Anthropogenic Conglomerate

Jewelry Chain with Blue and Clear Gemstones (Likely Cubic Zirconia)

Cubic Zirconia (ZrO₂), Silver or White Gold/Platinum Alloy

Polished labradorite pendant

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

Citrine Quartz

Citrine (Silicon Dioxide, SiO2)

Colorless quartz crystal (likely quartz fragment)

Quartz, silicon dioxide (SiO₂)

Polished silver sheen obsidian heart

Obsidian (volcanic glass), primarily rhyolitic silica-rich glass

Amethyst gemstone ring

Quartz, purple variety — SiO₂

Chert Arrowhead (Projectile Point)

Microcrystalline Quartz (Chert or Flint)

Goldstone (likely blue-free synthetic goldstone pendant)

Synthetic aventurine glass; silica glass with dispersed metallic copper crystals

Blue Goldstone

Goldstone (artificial glass)

Green sea glass (likely bottle glass)

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