Anthracite Coal
Anthracite (Carbon-rich mineraloid)
metamorphic
Category
Mineraloid (Anthropogenic)
Browse mineraloid (anthropogenic) specimens identified by the Rock Identifier community.
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Amber
Succinite (Organic Mineraloid) - C10H16O
mineral
Obsidian
Volcanic Glass (Silica-rich glass)
igneous
Obsidian
Volcanic glass
igneous
Chert (Arrowhead artifact)
Chert (Cryptocrystalline Silica, SiO2)
sedimentary
Pearl
Organic Mineraloid (CaCO3 + Conchiolin)
mineral
Chert (Yellow Jasper)
Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Arrowhead Fragment)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Arrowheads)
Microcrystalline Quartz (SiO2)
sedimentary
Concrete / Conglomerate (Man-made)
Artificial Conglomerate (Cementitious Composite)
sedimentary
Sea Glass
Amorphous Silicon Dioxide (Man-made glass weathered by nature)
mineral
Chert (Arrowhead Fragment)
Silicon Dioxide (SiO2)
sedimentary
Sea Glass
Man-made silicate glass
sedimentary
Obsidian
Volcanic Glass
igneous
Obsidian
Volcanic glass
igneous
Obsidian
Volcanic Glass
igneous
Obsidian
Volcanic Glass
igneous
Mahogany Obsidian
Volcanic glass (high silica) with inclusions of Magnetite or Hematite
igneous
Obsidian
Volcanic glass (SiO2 + impurities)
igneous
Chert Arrowhead
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Arrowhead)
Microcrystalline Quartz (SiO2)
sedimentary
Chert Arrowhead (Lithic Artifact)
Microcrystalline Quartz (SiO2)
sedimentary
Chert Arrowhead (Projectile Point)
Microcrystalline Quartz (SiO2)
sedimentary
Chert Arrowhead
Microcrystalline Quartz (SiO2)
sedimentary
Obsidian
Volcanic Glass (Amorphous SiO2)
igneous
Obsidian
Volcanic Glass
igneous
Limonite or Ironstone Nodule
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)
sedimentary
Black Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Chert (Arrowhead/Tool variety)
Microcrystalline Quartz (SiO2)
sedimentary
Asphalt Concrete
Bituminous Concrete (Anthropic Rock)
sedimentary
Green Sea Glass
Man-made vitreous material (silica glass)
gemstone
Mystic Topaz
Aluminum silicate fluoride hydroxide with titanium coating (Al2SiO4(F,OH)2)
mineral
Cupronickel (on a 1981 Mexico 20 Pesos coin)
Copper-Nickel Alloy (Cu75Ni25)
mineral
Slag
Anthropogenic Vitreous Silicate / Ferro-silicate Slag
igneous
Concrete
Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)
sedimentary (anthropogenic / man-made)
Painted River Pebble (likely Basalt or Greywacke)
Aphanitic Lithic Clast with Anthropogenic Pigment coating
Sedimentary or Igneous
Chert Arrowhead (Lithic Tool)
Microcrystalline quartz (SiO2) - Archeological lithic artifact
sedimentary
Obsidian
Volcanic Glass
igneous
Black Obsidian
Volcanic Glass (Amorphous SiO2)
igneous
Black Obsidian
Volcanic Glass (Amorphous SiO2 with trace impurities)
igneous
Chert (specifically Flint Arrowhead)
Silicon dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Likely weathered metallic mineral or slag fragment
Uncertain; possibly limonite/goethite-coated iron mineral, or industrial iron slag
mineral