Anthropogenic Material (Man Made Rock)

Iron Slag

Iron/Steel Slag (Ferrosilicate Glass)

Clear Quartz Sphere (Rock Crystal)

Silicon Dioxide (SiO2)

Blue-green faceted gemstone, possibly glass or synthetic material

Not identifiable from the image; possible synthetic spinel or glass

Slag Glass / Industrial Slag

Anthropogenic Glass

Decorative mosaic cross containing mixed rock and glass fragments

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

Eroded Brick or Pumice-like Scoria

Vesicular Basalt / Scoria (Anthropogenic variant: Eroded Firebrick)

Opalite

Synthetic Opalized Glass

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial Man-made)

Blue Obsidian (Cullet Glass)

Silicon Dioxide (Amorphous Glass)

Cobalt Blue Glass / Cullet Glass

Silicon dioxide (Amorphous man-made glass)

Asphalt Chunk (Bituminous Concrete)

Aggregated Bitumen / Artificial Breccia

Tumbled black stone, likely black obsidian

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

Polished obsidian

Volcanic glass; predominantly rhyolitic SiO₂

Opalite

Opalescent Glass (SiO2 + coloring agents)

Asphalt Concrete

Bituminous Concrete

Concretion (Sandstone)

Carbonate-cemented Sandstone Concretion

Green sea glass (likely)

Man-made glass, likely soda-lime silicate glass; not a natural mineral or rock

Slag (Industrial Byproduct)

Anthropogenic Vitreous Silicate material

Blue Goldstone

Man-made glass with cobalt and metal flecks

Slag

Anthropogenic Vitrification Product / Silicate Slag

Green Sea Glass

Amorphous Silica (man-made glass), SiO2 + additive metal oxides

Blue Goldstone

Synthetic glass with cobalt and copper inclusions

Green sea glass (likely)

Anthropogenic glass, not a mineral; composition commonly soda–lime silicate glass

One Pound Coin (UK)

Nickel-Brass Alloy (Cu-Zn-Ni)

Chert (Chalky Flint Node)

Chert (Microcrystalline Quartz, SiO2)

Opaline Glass (Opalite)

Synthetic Silicon Dioxide Glass

Tumbled Clear Quartz/Rock Crystal

Silicon Dioxide (SiO2)

Concrete fragment or Conglomerate

Artificial Conglomerate (Concrete) or Natural Conglomerate

Likely tumbled red mineral or glass imitation

Indeterminate; possibilities include red jasper (microcrystalline quartz, SiO₂) or dyed chalcedony

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Man-made Polished Porcelain Tile (Artificial Geologic Lookalike)

Fused Silicate Ceramic with Alumina (Synthetic Kaolinite derivative)

Purple glassy pebble, possibly slag glass

Unidentified; likely man-made glass rather than a natural mineral

Costume Jewelry with Synthetic Gemstones

Synthetic Cubic Zirconia and Glass (SiO2 / ZrO2)

Dzi Bead (Etched Chalcedony)

Cryptocrystalline Quartz (SiO2) with chemical etching

Sea Glass

Man-made vitreous material (silica-based glass)

Bouncy Ball (Synthetic Rubber Polymer)

Polybutadiene / Ethylene Vinyl Acetate (EVA)

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial Byproduct)

Crackled Quartz (Dyed)

Silicon Dioxide (SiO2)

Metal Alloy (Likely Pewter or Sterling Silver)

Not a natural geological specimen; composed of refined metals. If pewter, it's a tin-based alloy. If sterling silver, it's 92.5% silver and 7.5% other metals (usually copper).

Opalite

Man-made Glass (Synthetic Opalized Glass)

Chert (Arrowhead Shard)

Microcrystalline silica (SiO2)

Clay Brick

Ceramic structural unit (Al2O3·2SiO2·2H2O as precursor)