Quartz-rich rock fragment
Unidentified quartz–feldspar-rich rock; exact lithology cannot be determined from the image
igneous
Category
Mineral Precipitate (Anthropogenic Context)
Browse mineral precipitate (anthropogenic context) specimens identified by the Rock Identifier community.
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Chert (Flint variety)
Microcrystalline context of Quartz (SiO2)
sedimentary
Green Slag
Anthropogenic Silicate Glass
Mineraloid (Industrial byproduct)
Industrial Slag
Anthropogenic Vitreous Slag
igneous
Slag (Industrial Glass/Byproduct)
Anthropogenic Vitreous Silicate
igneous (anthropogenic)
Iron Slag
Anthropogenic pyrometallurgical byproduct
igneous
Iron Slag
Anthropogenic pyrometallurgical residue
industrial byproduct
Wishing Rock (Quartz Vein in Host Rock)
Silicon dioxide (SiO2) vein in various host rocks
Igneous/Sedimentary/Metamorphic with Mineral Vein
Fossil bivalve shell
Fossilized or partially mineralized bivalve; exact genus cannot be determined from the image
fossil
Kidney Stone
Calcium Oxalate (CaC2O4), Uric Acid, or Struvite
mineral
Nickel coin (U.S. currency)
Cupronickel (75% Copper, 25% Nickel alloy)
man-made alloy (metallic)
Dark flint or chert fragment
Microcrystalline quartz (SiO₂), likely chert/flint
sedimentary
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 cement)
sedimentary
Crackled Quartz (Blue Dyed)
Silicon Dioxide (SiO2) with anthropogenic dye
mineral
Slag (Industrial By-product)
Anthropogenic Vitreous Silica/Iron Silicate
mineral
Chert Nodules in Limestone
Microcrystalline Quartz (SiO2) in Carbonate Matrix
sedimentary
Vesicular Basalt
Aphanitic Mafic Volcanic Rock
igneous
Chert / Flint Tool
Cryptocrystalline quartz (SiO2)
sedimentary
Chert / Flint (Artifact)
Microcrystalline Quartz (SiO2)
sedimentary
Chert / Flint Arrowhead
Microcrystalline Quartz (SiO2)
sedimentary
Iron-rich concretion or slag-like mineral fragment
Likely limonite/goethite (FeO(OH)·nH₂O), possibly magnetite-bearing material
mineral
Pyrite in Matrix (likely Quartz or Schist matrix)
Iron Sulfide (FeS2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Fossil shell fragment (likely bivalve)
Bivalvia indeterminate; shell material chiefly aragonite or calcite (CaCO₃)
fossil
Sandstone
Arenite (primarily Quartz Sandstone)
sedimentary
Kidney Stone (Medical Specimen)
Calcium oxalate monohydrate (Whewellite) / CaC2O4·H2O
Mineral (Biogenic)
Green sea glass (likely bottle glass)
Human-processed soda–lime silicate glass; not a natural mineral or rock
mineral
Small dark mineral/rock fragment
Indeterminate; possibly magnetite-bearing basalt or iron-rich slag
mineral
Glauconitic Sandstone (or Greenstone)
Glauconitic Sandstone with Quartz
sedimentary
Sea Glass
Amorphous Silica (Anthropogenic glass) - SiO2
mineral
Stainless Steel (Polished)
Ferrous Alloy containing Iron (Fe), Chromium (Cr), and Carbon (C)
Mineral equivalent / Metal Alloy
Bronze or iron-age decorated pottery sherd
Archaeological ceramic fragment; likely fired clay with impressed or molded decoration, not a natural rock
fossil
Quartz crystal (likely milky or clear quartz)
Quartz, silicon dioxide (SiO₂)
mineral
Sandstone (likely Fossilized Wood or Concrete Simulacrum)
Arenite / Silicified Wood / Anthropogenic Concrete
sedimentary
Asphalt Concrete
Bituminous Concrete (Anthropic Rock)
sedimentary
Ironstone Concretion (Moqui Marble type)
Ironstone Concretion (Fe2O3 with SiO2 core)
sedimentary
Chert Arrowhead
Cryptocrystalline Quartz (SiO2)
sedimentary
Sea Glass
Amorphous Silicon Dioxide (Man-made glass weathered by nature)
mineral
Rhodonite
Manganese silicate (Mn,Fe,Mg,Ca)SiO3
mineral
Slag (Industrial Glassy Byproduct)
Anthropogenic silicate byproduct (Slag)
Mineral-like byproduct (often mistaken for igneous rock or meteorite)
Tumbled limestone or marble
Calcite-rich carbonate rock; likely limestone (CaCO₃), possibly marble
metamorphic
Likely garnet-bearing metamorphic fragment
Uncertain; possibly almandine garnet in mica schist or amphibolite
metamorphic