Not A Natural Rock (Man Made Composite)

Opalite

Synthetic Opalised Glass

Blue obsidian-like volcanic glass

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

Colorless quartz crystal (likely quartz fragment)

Quartz, silicon dioxide (SiO₂)

Opalite

Synthetic Opalite Glass (Silicon Dioxide)

Goldstone (Brown)

Aventurine Glass (Silicon Dioxide infused with Copper crystals)

Metal Chain Belt with Square Plates

Not applicable (man-made)

Concrete aggregate surface

Human-made cementitious composite; primarily calcium-silicate-hydrate cement with mixed silicate aggregate

One Pound Coin (UK)

Nickel-Brass Alloy (Cu-Zn-Ni)

Man-made Slag (Industrial Byproduct)

Anthropogenic Glassy Residue

Titanium Amethyst Geode

Silicon Dioxide (SiO2) with Titanium/Metal Vapor Deposition Layer

Green Glass (often marketed as 'Obsidian' or 'Green Quartz')

Amorphous Silica (SiO2) with copper or chromium additives

Opalite crescent pendant

Opalite (man-made opalescent glass; not a natural mineral)

Polished blue glassy mineral specimen, likely sodalite or blue aventurine

Most consistent with sodalite (Na₈Al₆Si₆O₂₄Cl₂), though dyed quartzite or blue glass cannot be excluded from the photograph

Blue glassy gemstone cabochon, likely dyed chalcedony or glass

Uncertain; possible dyed chalcedony (microcrystalline quartz, SiO₂)

Concrete Rubble with Aggregate

Hardened Portland Cement Paste with Coarse Aggregate

Agate and millefiori glass jewelry

Agate: microcrystalline quartz (SiO₂); millefiori element appears to be man-made glass

Dyed Agate

Chalcedony (SiO2)

Goldstone

Avventurina (Man-made Glass with Copper inclusions)

Man-made Carved Stone (Scream Mask/Skull motif)

Carved Soapstone or Serpentine-rich rock

Goldstone (aventurine glass)

Man-made copper-bearing glass; not a natural mineral (commonly sold as blue/brown goldstone)

Opalite (likely imitation opal glass)

Man-made opalescent glass; not a natural mineral (often sold as opalite)

Obsidian (Blue)

Volcanic Glass (SiO2)

Blue Slag Glass

Man-made Silicon Dioxide (Amorphous)

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂), opaque-to-translucent milky variety

Porcelain (Stoneware Ceramic)

Mullite / Silica-glass composite (Al6Si2O13)

Blue cabochon gemstone, likely synthetic glass or dyed stone

Indeterminate from image; possible glass, synthetic spinel, sodalite, or lapis lazuli

Aura Quartz

Titanium-coated Silicon Dioxide (SiO2)

Aura Rose Quartz

SiO2 (Silicon Dioxide with Titanium/Gold coating)

Aura Quartz (Rainbow Quartz)

Silicon Dioxide (SiO2) with metallic vapor coatings

Man-made Glass (Tumbled/Shaped)

Amorphous Silicon Dioxide (SiO2) with metal oxide colorants

Green Sea Glass

Man-made vitreous material (silica glass)

Tumbled opalite (likely man-made glass)

Opalite, a trade name for opalescent glass; not natural opal

Diamond

Carbon (C)

Tumbled white chalcedony (likely milky quartz)

Chalcedony, microcrystalline quartz (SiO₂)

Titanium Aura Quartz (Bismuth-coated Druzy)

Silicon Dioxide (SiO2) with Titanium/Metal vapor coating

Cubic Zirconia (Diamond Simulant)

Zirconium Dioxide (ZrO2)

Concretion (Sandstone)

Carbonate-cemented Sandstone Concretion

Sea Glass

Amorphous Silicon Dioxide (SiO2)

Opal ring (likely precious opal)

Hydrated amorphous silica, SiO₂·nH₂O; the pictured stone may be natural opal or a lab-created/imitation opal

Asphalt Concrete

Bituminous Concrete (Anthropic Rock)

Opalite

Synthetic Glass (Simulated Opal)

Polished turquoise matrix beads

Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O, with host-rock matrix; exact identification is uncertain from the image