Mineraloid (Man Made Glass)

Tumbled gray stone, likely quartz-rich pebble

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

Blue Obsidian (Cullet Glass)

Silicon Dioxide (Amorphous Glass)

Opalite (likely man-made opalescent glass)

Opalite; not a true mineral, typically synthetic opalescent glass (silica-based)

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

Decorative mosaic cross containing mixed rock and glass fragments

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

Blue Goldstone

Aventurine Glass

Opalite

Synthetic Glass (Simulated Moonstone/Opal)

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.”

Opalite

Man-made Synthetic Glass (Silicon Dioxide with metal additives)

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)

Blue Goldstone

Synthetic Avanturine Glass (or Aventurine Glass)

Polished white chalcedony or quartz pendant

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

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 glassy-looking specimen, possibly dyed or coated mineral

Not identifiable from the photograph; possibilities include dyed quartz or glassy slag, but composition cannot be established visually.

Green sea glass (likely bottle glass)

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

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

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

Green Glass Slag

Amorphous Silicon Dioxide (SiO2) with metal oxide impurities

Mystic Topaz (Treated Quartz or Topaz)

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

Sandstone Concretion

Limonitic Sandstone Concretion

Polished silver sheen obsidian heart

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

Polished labradorite pendant

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

Citrine Quartz

Citrine (Silicon Dioxide, SiO2)

Pearl

Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin

Ferrous Slag

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