Concrete / Anthropogenic Conglomerate
Man-made composite material (Portland cement, aggregate, and water)
not a natural rock
Category
Mineral Precipitate (Anthropogenic Context)
Browse mineral precipitate (anthropogenic context) specimens identified by the Rock Identifier community.
Learn about Mineral Precipitate (Anthropogenic Context) in the encyclopedia
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Greenstone (Celadonite-bearing Volcanic)
Hydrothermally altered basalt or andesite with Celadonite (K(Mg,Fe2+)(Fe3+,Al)Si4O10(OH)2)
metamorphic
Sulfidic Mudstone with Pyrite/Goethite
Sulfidic Siltstone/Mudstone (FeS2)
sedimentary
Chert (Arrowhead/Projectile Point)
Microcrystalline quartz (SiO2)
sedimentary
Chert (Arrowhead)
Chert (SiO2)
sedimentary
Chert (Arrowhead Fragment)
Microcrystalline Quartz (SiO2)
sedimentary
Red Jasper (Mookaite style)
Silicon Dioxide (SiO2) with iron oxide impurities
sedimentary
Fossiliferous Limestone with Crinoid Stem fragment
Calcite (CaCO3) containing Crinoidea fossils
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Chert (often called Flint)
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Ferrochrome Slag
Anthropogenic slag (Fe-Cr alloy waste)
industrial byproduct
Chert (specifically a Lithic Flake)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
sedimentary
Synthetic Faux Fur Fursuit
Polyacrylonitrile / Polyester (Synthetic Textile)
not a rock (synthetic material/costume)
Basalt Metate
Vesicular Basalt
igneous
Amethyst (Tumbled/Weathered Quartz)
Amethyst (SiO2 with iron impurities)
mineral
Black Onyx
Black Chalcedony (SiO2)
mineral
Olivine Diabase Porphyry
Porphyritic Olivine-Bearing Diabase (Micro-Gabbro)
igneous
Sandstone Concretion
Ferruginous Sandstone Concretion (Primarily SiO2 with Iron Oxide cement)
sedimentary
Sea Shell (Fighting Conch Fragment)
Calcium Carbonate (CaCO3) - Strombus alatus fragment
sedimentary (biogenic)
Chert Arrowhead
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Septarian or Nodular variety)
Microcrystalline Quartz (SiO2)
sedimentary
Yellow Ochre / Limonite
Hydrated ferric oxide (FeO(OH)·nH2O)
mineral
Schist (Biotite/Mica Schist)
Medium-grade regional metamorphic rock (rich in Phyllosilicates)
metamorphic
Weathered quartz-rich rock, likely sandstone or quartzite
Quartz (SiO₂)-rich sandstone; possibly partially metamorphosed quartzite
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2)
sedimentary
Peridotite (Olivine)
Peridotite (comprising (Mg,Fe)2SiO4)
igneous
Greenstone
Greenschist (composed of chlorite, actinolite, and epidote)
metamorphic
Ironstone Concretion
Limonitic/Hematitic Concretion
sedimentary
Ferruginous Quartzite (also known as Ironstone or Gossan)
Ferruginous Quartzite with Goethite/Hematite staining
metamorphic
Weathered sandstone or iron-rich sedimentary fragment
Quartz-rich sandstone, possibly ferruginous sandstone (SiO₂-dominant)
sedimentary
Chert (varietal Chalcedony or Flint)
Silicon dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Chert (Yellow Jasper)
Cryptocrystalline Quartz (SiO2)
sedimentary
Granite Pebble
Granite (Phaneritic intrusive igneous rock comprising Quartz, Feldspar, and Mica)
igneous
Jasper with Iron Staining
Silicon Dioxide (SiO2) with impurities
sedimentary
Fuchsite
K(Al,Cr)2(AlSi3O10)(OH)2 (Chromium-rich Muscovite)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Chert (Arrowhead Artifact)
Microcrystalline Quartz (SiO2)
sedimentary
Chert Arrowhead (Lithic Artifact)
Microcrystalline Quartz (SiO2)
sedimentary
Chert Arrowhead (Lithic Artifact)
Chert (Cryptocrystalline Quartz, SiO2)
sedimentary