Not A Natural Rock (Man Made Composite)

Tumbled blue stone, likely blue aventurine or dyed chalcedony

Aventurine quartz (SiO₂) or chalcedony (microcrystalline SiO₂); exact identification requires testing

Cubic Zirconia (Simulated Diamond)

Cubic Zirconia (ZrO2)

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Strawberry Quartz

Silicon Dioxide (SiO2) with Hematite/Goethite inclusions

Asphalt aggregate pavement

Bituminous asphalt concrete containing crushed stone aggregate

Rainbow Hematite (Man-made/Treated)

Tumbled Hematite with Titanium/Anodized coating (Iron(III) oxide, Fe2O3)

Faceted glass-like gemstone (likely synthetic quartz or cubic zirconia)

Identification uncertain; possibilities include synthetic quartz (SiO₂) or cubic zirconia (ZrO₂)

Rounded graywacke or sandstone cobble

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

Milky quartz

Quartz (silicon dioxide, SiO₂)

Carnelian (red-orange chalcedony) beads

Microcrystalline quartz, SiO₂; chalcedony colored chiefly by iron oxides

Nacre (Mother of Pearl)

Nacre (Biogenic Aragonite/Calcite composite, CaCO3)

Goldstone (Red)

Aventurine Glass (Cupriferous glass)

Engineered Quartz

Engineered Stone (primarily SiO2)

Aura Quartz

Titanium/Titanium-Gold treated Silicon Dioxide (SiO2)

Clear quartz crystal (likely)

Quartz, silicon dioxide (SiO₂)

Colorless faceted gemstone (most likely synthetic cubic zirconia)

Cubic zirconia, ZrO₂ (likely synthetic); natural alternatives include quartz or diamond

Blue glassy tumbled stone, likely blue chalcedony or slag glass

Chalcedony (microcrystalline SiO₂), possibly man-made blue glass

Conglomerate

Clastic Sedimentary Rock (Conglomerate)

Green sea glass or tumbled green quartz (uncertain)

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

Pink Tumbled Quartz (Dyed)

Silicon Dioxide (SiO2)

Blue Goldstone

Synthetic Avanturine Glass (or Aventurine Glass)

Sandstone Concretion

Clastic Sedimentary Concretion (SiO2 with Iron Oxide)

Dyed Blue Agate (Dragon Vein Agate)

Silicon Dioxide (SiO2) with artificial cobalt/organic dyes

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂), likely milky quartz

Mixed polished gemstone bead bracelet, likely ocean jasper, agate, and quartz varieties

Mostly microcrystalline quartz (SiO₂), with possible chalcedony, jasper, and minor feldspar or other inclusions

Brick veneer, likely manufactured from clay-rich shale

Fired clay brick; chiefly aluminosilicate minerals, commonly mullite and glassy silicate phases after firing

Goldstone (Brown/Gold variety)

Aventurine Glass (SiO2 with Copper inclusions)

Polished black stone, likely obsidian

Obsidian (volcanic glass; mostly silica-rich rhyolitic composition)

Sea Glass

Man-made silicate glass

Sea Glass

Man-made silicate glass

Sea Glass

Man-made silicate glass

Sea Glass

Man-made vitreous material

Sea Glass

Man-made vitreous material

Transit Token (RTD Denver)

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

Sea Glass

Man-made silicate glass

Sea Glass

Man-made silicate glass

Sea Glass

Man-made silicate glass

Slag Glass

Amorphous Silicate (Man-made)

Blue opal heart cabochon

Common opal, hydrated amorphous silica (SiO₂·nH₂O), likely blue-dyed or synthetic opalite

Decorative opal-like turtle mosaic

Likely imitation or assembled opal material; exact stones cannot be confirmed visually

Slag Glass

Anthropogenic Amorphous Silicon Dioxide

Sea Glass

Amorphous silicon dioxide