Sedimentary (Anthropogenic)

Grooved Maun Ball (Maul/Hammerstone-like Concretion)

Calcareous/Ferruginous Concretion in Sandstone Matrix

Iron-rich concretion or slag-like mineral fragment

Likely limonite/goethite (FeO(OH)·nH₂O), possibly magnetite-bearing material

Conglomeratic gravel / polymictic breccia

Polymictic rudite, likely anthropogenic or beach/stream gravel; composition varies

Sea Glass

Amorphous Silicon Dioxide (Man-made glass weathered by nature)

Concrete

Anthropogenic Sedimentary Conglomerate (Cement mixture: typically Ca2SiO4, Ca3SiO5, Ca3Al2O6)

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial byproduct)

Green Sea Glass

Man-made vitreous material (silica glass)

Mystic Topaz

Aluminum silicate fluoride hydroxide with titanium coating (Al2SiO4(F,OH)2)

Cupronickel (on a 1981 Mexico 20 Pesos coin)

Copper-Nickel Alloy (Cu75Ni25)

Likely weathered metallic mineral or slag fragment

Uncertain; possibly limonite/goethite-coated iron mineral, or industrial iron slag

Basalt

Basalt (Mafic volcanic rock)

Obsidian Arrowhead

Obsidian (Volcanic Glass)

Slag

Anthropogenic Vitreous Silicate / Ferro-silicate Slag

Titanium Aura Quartz (Bismuth-coated Druzy)

Silicon Dioxide (SiO2) with Titanium/Metal vapor coating

Ferrochrome Slag

Anthropogenic slag (Fe-Cr alloy waste)

Slag (Industrial Glass)

Anthropogenic Vitreous Slag (Post-industrial byproduct)

Cobalt Blue Slag Glass

Amorphous Silicon Dioxide (anthropogenic) with Cobalt additives

Possible tektite or iron-rich slag-like natural specimen

Uncertain; possibly natural glass (tektite) or magnetite-rich rock

Possible tektite or volcanic glass specimen

Natural silica glass; composition commonly near SiO₂, but exact identification requires chemical testing

Ceramic or Polished Stone Heart (Anthropogenic Material)

Glazed Ceramic (Silicon Dioxide based coating on Alumina Silicate body) or Polished Limestone/Marble (Calcium Carbonate, CaCO3)

Basalt

Basalt (Mafic Extrusive Igneous Rock)

Greenstone Celt (Polished Stone Axe)

Metamorphosed mafic rock (often Basalt or Diabase)

Possible basaltic volcanic rock or iron-rich meteorite

Likely basalt (plagioclase–pyroxene rock); meteorite status cannot be confirmed visually

Blue slag glass / industrial smelter slag

Man-made iron-rich silicate slag; composition variable, commonly Fe–Ca–Mg–Al silicates with glassy phases

Iron-rich slag or weathered ironstone fragments

Probably hematite–goethite material; possibly industrial iron slag (Fe₂O₃/FeO(OH))

Banded Slag Glass (Leland Blue/Frankfort Green style)

Anthropogenic Glass Specimen (Amorphous Silicon Dioxide with impurities)

Eroded Brick or Pumice-like Scoria

Vesicular Basalt / Scoria (Anthropogenic variant: Eroded Firebrick)

Granite Pebble

Granite (Phaneritic intrusive igneous rock comprising Quartz, Feldspar, and Mica)

Ferruginous Slag (Iron Smelting Byproduct)

Anthropogenic Vitreous Silicate (often containing Fayalite: Fe2SiO4)

Quartzite Arrowhead (Archaeological Lithic)

Recrystallized Quartz (SiO2)

Metal Chain (Likely Steel or a Steel Alloy)

Steel (primarily iron and carbon); specific alloy unknown

Slag (Anthropogenic Glass/Iron byproduct)

Ferro-silicate Slag

Obsidian Arrowhead

Volcanic Glass (Primary composition: SiO2)

Iron-rich vesicular rock, possibly slag or weathered basalt

Identification uncertain; likely ferruginous basalt/ironstone, with possible anthropogenic iron slag

Green sea glass or green glass-like tumbled material

Amorphous silicate glass; likely anthropogenic soda-lime glass, not a natural mineral

Slag (Industrial Glass)

Artificial Vitreous Silicate

Sea Glass

Amorphous Silica (SiO2) with various additives

Slag

Ferrous slag (by-product of iron smelting)

Asphalt fragment

Bituminous concrete

Paper (Cellulose)

Cellulose (C6H10O5)n

Green Slag Glass

Amorphous Silicon Dioxide (with metallic impurities)

Cullet (Slag Glass)

Amorphous Silica (SiO2) with various metal oxide colorants