Small dark mineral/rock fragment
Indeterminate; possibly magnetite-bearing basalt or iron-rich slag
Category
Browse sedimentary (anthropogenic) specimens identified by the Rock Identifier community.
Small dark mineral/rock fragment
Indeterminate; possibly magnetite-bearing basalt or iron-rich slag
Slag
Glassy silicate byproduct (anthropogenic material)
Slag
Anthropogenic Vitrophyre (Iron or Smelting Slag)
Iron Slag (Industrial Byproduct)
Anthropogenic Vitrification Product/Ferrous Slag
Sea Glass
Amorphous Silica (Anthropogenic glass) - SiO2
Ferro-slag (Leland Blue/Slag Glass)
Anthropogenic Vitreous Silica (Industrial Slag)
Conglomeratic gravel / polymictic breccia
Polymictic rudite, likely anthropogenic or beach/stream gravel; composition varies
Asphalt (Bituminous Concrete)
Asphaltum / Bitumen-Aggregate Matrix
Concrete
Anthropogenic Sedimentary Conglomerate (Cement mixture: typically Ca2SiO4, Ca3SiO5, Ca3Al2O6)
Iron-rich concretion or slag-like mineral fragment
Likely limonite/goethite (FeO(OH)·nH₂O), possibly magnetite-bearing material
Grooved Maun Ball (Maul/Hammerstone-like Concretion)
Calcareous/Ferruginous Concretion in Sandstone Matrix
Sea Glass
Amorphous Silicon Dioxide (Man-made glass weathered by nature)
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)
Slag
Anthropogenic Vitreous Silicate / Ferro-silicate Slag
Likely weathered metallic mineral or slag fragment
Uncertain; possibly limonite/goethite-coated iron mineral, or industrial iron slag
Basalt
Basalt (Mafic volcanic rock)
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
Obsidian Arrowhead
Obsidian (Volcanic Glass)
Titanium Aura Quartz (Bismuth-coated Druzy)
Silicon Dioxide (SiO2) with Titanium/Metal vapor coating
Ceramic or Polished Stone Heart (Anthropogenic Material)
Glazed Ceramic (Silicon Dioxide based coating on Alumina Silicate body) or Polished Limestone/Marble (Calcium Carbonate, CaCO3)
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
Greenstone Celt (Polished Stone Axe)
Metamorphosed mafic rock (often Basalt or Diabase)
Basalt
Basalt (Mafic Extrusive Igneous Rock)
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)
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))
Ferruginous Slag (Iron Smelting Byproduct)
Anthropogenic Vitreous Silicate (often containing Fayalite: Fe2SiO4)
Granite Pebble
Granite (Phaneritic intrusive igneous rock comprising Quartz, Feldspar, and Mica)
Quartzite Arrowhead (Archaeological Lithic)
Recrystallized Quartz (SiO2)
Slag (Anthropogenic Glass/Iron byproduct)
Ferro-silicate Slag
Metal Chain (Likely Steel or a Steel Alloy)
Steel (primarily iron and carbon); specific alloy unknown
Obsidian Arrowhead
Volcanic Glass (Primary composition: SiO2)
Green sea glass (likely)
Anthropogenic glass, not a mineral; composition commonly soda–lime silicate glass
Iron-rich vesicular rock, possibly slag or weathered basalt
Identification uncertain; likely ferruginous basalt/ironstone, with possible anthropogenic iron slag