Opalite
Synthetic Opalised Glass
Mineral (Synthetic / Man-made)
Category
Anthropogenic Material (Man Made Rock)
Browse anthropogenic material (man made rock) specimens identified by the Rock Identifier community.
Learn about Anthropogenic Material (Man Made Rock) in the encyclopedia
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Beach Pebble (Chalcedony / Chert)
Silicon Dioxide (SiO2)
mineral
Possible basaltic volcanic rock or iron-rich meteorite
Likely basalt (plagioclase–pyroxene rock); meteorite status cannot be confirmed visually
igneous
Iron-rich slag or weathered ironstone fragments
Probably hematite–goethite material; possibly industrial iron slag (Fe₂O₃/FeO(OH))
mineral
Flint (chert) nodule
Microcrystalline quartz (SiO₂), occurring as a flint/chert nodule in limestone
sedimentary
Polished orbicular granite heart
Granite, commonly quartz–alkali feldspar–plagioclase–biotite granite; exact locality-dependent
igneous
Pumice or vesicular volcanic tuff
Pumice: highly vesicular volcanic glass, chiefly rhyolitic to dacitic; possible tuff: lithified ash and pumice fragments
igneous
Small dark mineral/rock fragment
Indeterminate; possibly magnetite-bearing basalt or iron-rich slag
mineral
Red Sandstone
Quartz Arenite (iron-stained) / SiO2
sedimentary
Chert (Arrowhead/Tool variety)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite (variable SiO2 composition)
sedimentary
Sandstone
Arenite (SiO2 primarily)
sedimentary
Greenstone Celt (Polished Stone Axe)
Metamorphosed mafic rock (often Basalt or Diabase)
metamorphic
Chert (Flint)
SiO2 (Microcrystalline Quartz)
sedimentary
Chert (Black Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint / Jasper)
Silicon Dioxide (SiO2)
sedimentary
Coquina (Fossiliferous Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Likely clear quartz crystal or glass-like gemstone
Quartz, silicon dioxide (SiO₂); exact identification is uncertain from the strongly magenta-lit image
mineral
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
mineral
Nephrite Jade
Nephrite
Mineral/Rock
Tumbled yellow jasper or chalcedony
Microcrystalline quartz, SiO₂; likely iron-oxide-bearing jasper/chalcedony
mineral
Sandstone
Arenite
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Anthropogenic Heat Source (Electronic/Industrial Interface)
Thermal IR emission (Electronic infrastructure)
not a rock or mineral
Green Agate
Silicon dioxide (SiO₂)
mineral
Concrete or asphalt-like aggregate surface with a dark fragment
Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock
sedimentary
Colorless faceted quartz-like gemstone
Likely quartz (SiO₂), though the appearance may also indicate man-made glass or cubic zirconia
gemstone
Quartzite
Metamorphic quartz rock (SiO2)
metamorphic
Chert Arrowhead
Microcrystalline Quartz (SiO2)
sedimentary
Goldstone (Red/Brown)
Aventurine Glass (SiO2 with Copper inclusions)
Mineral (Man-made glass)
Sandstone (with iron staining)
Quartz Arenite / Ferruginous Sandstone
sedimentary
Chalk
Carbonate rock (mainly CaCO3)
sedimentary
Conglomerate (Asphaltic/Anthropogenic)
Clastic sedimentary rock / Bituminous mixture
sedimentary
Sandstone
Clastic sedimentary rock (Quartz arenite/Arkose)
sedimentary
Aventurine
Quartz containing inclusions of Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
metamorphic
Tumbled black stone, likely black obsidian
Obsidian; volcanic glass, typically rhyolitic composition (SiO₂-rich)
igneous
Sandstone
Sandstone (composed predominantly of Quartz, SiO2, with Feldspar and Clay minerals)
sedimentary
Rainbow Hematite (Man-made/Treated)
Tumbled Hematite with Titanium/Anodized coating (Iron(III) oxide, Fe2O3)
mineral
Sandstone (likely Quartzose Sandstone)
Arenite
sedimentary
River Pebbles (Chert and Quartzite)
Sedimentary Clastic Rock (Silica-rich)
sedimentary
Man-made Dyed Aura Quartz
Silicon Dioxide (SiO2) with metallic coating/dye
mineral