Sedimentary (Man Made)

Quartz (Engineered Stone Countertop)

Silicon Dioxide (SiO2) with polymer resins

Unidentified translucent crystal/mineral fragment

Likely quartz (SiO₂), but visual identification is uncertain

Asphalt (Bituminous pavement)

Bituminous concrete / Asphalt

Goldstone

Man-made glass with copper inclusions

Sandstone Concretion

Septarian or Carbonate-cemented Sandstone Concretion

Magnetic Hematite (Man-made)

Iron Oxide (Fe2O3) with Barium-Strontium Ferrite

Porcelain Tile (Sandstone-look)

Man-made Ceramic (resembling Quartz-rich Sandstone)

Opalite

Synthetic Opalite Glass / Opalized Glass

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (SiO2) with metallic oxide impurities

Slag (Industrial Byproduct)

Artificial silicate/iron byproduct

Titanium Coated Kyanite (Aura Kyanite)

Aluminosilicate (Al2SiO5) with a Titanium-Niobium vacuum-deposited coating

Sandstone (with concrete/human-made layer)

Clastic Sedimentary Rock (primarily Quartz/Feldspar grains)

Green Obsidian Sphere (man-made glass)

Vitreous Silica with Chromium/Iron additives

Opalite

Synthetic Opalite (Man-made glass)

Opalite

Man-made Glass (SiO2 + additives)

Transit Token (RTD Denver)

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

Decorative mosaic cross containing mixed rock and glass fragments

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

Goldstone

Man-made glass with copper inclusions

Blue Slag Glass

Man-made Silicon Dioxide (Amorphous)

Cullet Glass (Slag)

Amorphous Silicon Dioxide (Man-made)

Chert Concretion

Chert (Microcrystalline Quartz, SiO2)

Crescent Pebble

Weathered Quartzite or Sandstone Fragment

Boxwork or Septarian Concretion

Septarian nodule / Boxwork weathering

Likely iron-rich slag or weathered ironstone fragment

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

Blue-green faceted gemstone, possibly glass or synthetic material

Not identifiable from the image; possible synthetic spinel or glass

Mystic Topaz (Treated Quartz or Topaz)

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

Opalite

Man-made opalescent glass (SiO2 + metal oxides)

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Concrete

Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)

Faceted clear gemstone in a gold-colored setting

Unidentified transparent faceted stone; possibly quartz, glass, or another colorless gem

Concrete Rubble with Aggregate

Hardened Portland Cement Paste with Coarse Aggregate

Obsidian

Volcanic glass

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial Man-made)

Sandstone Anvil / Nutting Stone

Quartzose Sandstone (Sedimentary Rock)

Sea Glass

Man-made vitreous material / Silicon dioxide

Rounded graywacke or sandstone cobble

Lithified clastic sandstone; likely quartz–feldspar–lithic grain aggregate in a silica or calcite matrix

Concrete with Exposed Aggregate

Anthropogenic conglomerate (Concrete)

Baked-clay ceramic fragment (likely brick or pottery)

Fired clay, primarily aluminosilicate minerals; not a natural rock

Titanium-coated Metal Cube (Man-made Fidget Toy)

Titanium-anodized or electroplated alloy (e.g., Ti-coated Zinc or Aluminum)

Blue Diamond

Carbon with Boron impurities (C)

Clear Quartz Sphere (Rock Crystal)

Silicon Dioxide (SiO2)

Blue Goldstone

Auraventurine (Synthetic glass with cobalt and copper inclusions)