Man Made Rock (Sedimentary Analogue)

Weathered rock fragment (likely granite or quartz-rich sandstone)

Uncertain; possible granitic fragment containing quartz and feldspar

Sandstone (with concrete/human-made layer)

Clastic Sedimentary Rock (primarily Quartz/Feldspar grains)

Weathered iron-rich concretion or ironstone nodule

Goethite–hematite limonite concretion (FeO(OH), Fe₂O₃, and hydrated iron oxides)

Opalite

Synthetic glass / Opalized glass

Boxwork or Septarian Concretion

Septarian nodule / Boxwork weathering

Sandstone Concretion

Septarian or Carbonate-cemented Sandstone Concretion

Concrete Fragment

Artificial Conglomerate (Cement and Aggregate)

Chakra Stone (Composite / Man-made Bonded Gemstones)

Composite of Quartz, Lapis Lazuli, Aventurine, Tiger's Eye, and Jasper (SiO2, (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2, etc.)

Decorative mosaic cross containing mixed rock and glass fragments

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

Quartz pebble (Quartztite fragment)

Silicon Dioxide (SiO2)

Clear Quartz Sphere (Rock Crystal)

Silicon Dioxide (SiO2)

Sandstone (with Liesegang rings or joints)

Clastic Sedimentary Rock (primarily Quartz with Iron Oxide cement)

Asphalt Chunk (Bituminous Concrete)

Aggregated Bitumen / Artificial Breccia

Chert Concretion

Chert (Microcrystalline Quartz, SiO2)

Conglomerate

Conglomerate Rock (Paraconglomerate)

Concrete Rubble with Aggregate

Hardened Portland Cement Paste with Coarse Aggregate

Metal Chain Belt with Square Plates

Not applicable (man-made)

Concrete

Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)

Opalite

Man-made Glass (SiO2 + additives)

Baked-clay ceramic fragment (likely brick or pottery)

Fired clay, primarily aluminosilicate minerals; not a natural rock

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (SiO2) with metallic oxide impurities

Blue Slag Glass

Man-made Silicon Dioxide (Amorphous)

Slag

Metallurgical Slag

Blue Goldstone

Man-made glass with cobalt and metal flecks

White pebble, likely quartz or calcite

Indeterminate from image; possible microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Cullet Glass / Slag Glass

Amorphous silica glass

One Pound Coin (UK)

Nickel-Brass Alloy (Cu-Zn-Ni)

Blue-gray quartz-bearing rock, likely rough chalcedony or silicified host rock

Microcrystalline quartz (SiO₂), possibly with iron-oxide staining and minor feldspar/clay minerals

Asphalt (Bituminous Concrete)

Bituminous mix containing aggregates and petroleum-based binder (CnH2n+2)

Sandstone Concretion

Clastic sedimentary rock (primarily Quartz SiO2)

Asphalt Concrete

Bituminous Concrete

Concrete / Anthropogenic Conglomerate

Man-made composite material (Portland cement, aggregate, and water)

Dyed Agate / Painted Stone

Silicon Dioxide (SiO2) with artificial pigment

Sandstone Concretion

Limonitic Sandstone Concretion

Sandstone Concretion

Clastic Sedimentary Rock (primarily SiO2 with mineral cement)

Small tan rock fragment

Indeterminate; possibly quartz-rich sandstone or iron-stained quartz

Dzi Bead (Etched Chalcedony)

Cryptocrystalline Quartz (SiO2) with chemical etching

Slag

Anthropogenic Vitreous Silica/Iron oxides

Opalite

Man-made Glass (Synthetic Opalized Glass)

Asphalt (Bituminous pavement)

Bituminous concrete / Asphalt

Green Sea Glass

Man-made silicate glass (weathered)