Polished black stone, likely obsidian
Obsidian (volcanic glass; mostly silica-rich rhyolitic composition)
Category
Browse man made object (metalwork) specimens identified by the Rock Identifier community.
Polished black stone, likely obsidian
Obsidian (volcanic glass; mostly silica-rich rhyolitic composition)
Black tumbled stone, possibly obsidian
Obsidian (volcanic glass; predominantly SiO₂), identification uncertain from image
Sea Glass
Amorphous Silicon Dioxide (Man-made glass weathered by nature)
Quartz pebble (Quartztite fragment)
Silicon Dioxide (SiO2)
Stainless Steel (Polished)
Ferrous Alloy containing Iron (Fe), Chromium (Cr), and Carbon (C)
Green sea glass (likely bottle glass)
Man-made soda-lime silicate glass; not a natural mineral
Cobalt Blue Glass / Cullet Glass
Silicon dioxide (Amorphous man-made glass)
Chert (Arrowheads)
Microcrystalline Quartz (SiO2)
Blue chalcedony (likely dyed or treated)
Microcrystalline quartz, SiO₂ (chalcedony)
Sandstone Concretion
Clastic sedimentary rock (primarily Quartz SiO2)
Exposed Aggregate Concrete (Pea Gravel)
Concrete with Siliceous Alluvial Gravels
Milky quartz (likely quartz crystal fragment)
Quartz, silicon dioxide (SiO₂)
Orgonite Pyramid (containing Amethyst and mixed minerals)
Silicon Dioxide (SiO2) in synthetic resin
Tumbled milky chalcedony (likely common opalite-like quartz)
Chalcedony, microcrystalline SiO₂; possibly pale common opal, hydrated SiO₂·nH₂O
Concrete Fragment
Hardened Portland cement and mineral aggregate
Polished obsidian
Volcanic glass; predominantly rhyolitic SiO₂
Opalite
Synthetic Opalite Glass / Opalized Glass
Asphalt Concrete
Bituminous conglomerate
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (SiO2) with metallic oxide impurities
Slag (Industrial Byproduct)
Artificial silicate/iron byproduct
Green Obsidian Sphere (man-made glass)
Vitreous Silica with Chromium/Iron additives
Tumbled black stone, likely black obsidian
Obsidian; volcanic glass, typically rhyolitic composition (SiO₂-rich)
Transit Token (RTD Denver)
Nickel-plated brass or bronze alloy (Cu-Sn-Zn-Ni)
Mystic Topaz (Treated Quartz or Topaz)
Aluminum silicate fluoride hydroxide [Al2SiO4(F,OH)2] with thin-film metallic coating
Sandstone Concretion
Limonitic Sandstone Concretion
Asphalt (Road Aggregate)
Bituminous conglomerate
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
Blue glass-like bead or gemstone keychain ornament
Indeterminate; likely cobalt-blue glass or synthetic blue spinel, not identifiable as a natural mineral from the image
Terrazzo (Man-made Composite)
Cementitious or Resin-bound Lithic Composite
Crushed Stone (Likely Limestone or Granite)
Calcium Carbonate (CaCO3) for Limestone / Quartz and Feldspar for Granite
Likely citrine or yellow glass imitation in a silver-tone bracelet
Citrine: quartz, SiO₂; exact material cannot be confirmed visually
Concrete Rubble with Aggregate
Hardened Portland Cement Paste with Coarse Aggregate
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (Industrial Man-made)
Opalite
Synthetic Opalite (Man-made glass)
Opalite
Man-made Glass (SiO2 + additives)
Blue Slag Glass
Man-made Silicon Dioxide (Amorphous)
Cullet Glass (Slag)
Amorphous Silicon Dioxide (Man-made)
Green Sea Glass
Man-made silicate glass (weathered)
Concrete Paver (Artificial Cementitious Rock)
Hydrated Portland Cement Aggregate
Unidentifiable Rock Fragment
Asphalt Concrete (Bituminous Conglomerate)
Anthropogenic Bituminous Conglomerate
Concrete
Anthropogenic Conglomerate