Yellow Quartz (Citrine Quartz Pebble)
Silicon Dioxide (SiO2)
mineral
Category
Anthropogenic (Man Made Material Processed By Nature)
Browse anthropogenic (man made material processed by nature) specimens identified by the Rock Identifier community.
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Rough Diamond
Diamond (pure carbon, C)
mineral
Sandstone Flagstone
Arenite (SiO2 with various cementing agents)
sedimentary
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Sandstone
Clastic sedimentary rock (primarily quartz arenite)
sedimentary
Weathered greenstone (likely serpentinite or altered basalt)
Serpentinite-group rock, commonly dominated by serpentine minerals (antigorite/lizardite); exact identification requires testing
metamorphic
Sandstone
Arenite (a specific type of sandstone with less than 15% matrix)
Sedimentary rock
Sandstone (Ferruginous)
Arenite (with Hematite/Limonite cement)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Sandstone (Nut-stone / Cup-stone artifact)
Quartz Arenite / Worked Sedimentary Rock
sedimentary
Diamond
Carbon (C)
gemstone
Sandstone
Sedimentary Rock (Quartz Arenite)
sedimentary
Diamond
C (Carbon)
gemstone
Sandstone
Arenite
sedimentary
Green Aventurine
Aventurine (a variety of Quartz, SiO2 with fuchsite inclusions)
Mineral
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone
Clastic sedimentary rock (Quartz arenite / Arkose)
sedimentary
Turquoise cabochon
Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O
mineral
Sandstone (Quartzose)
Arenite (composed mainly of SiO2)
sedimentary
Anthracite Coal
Anthracite (Carbon-based metamorphic rock)
metamorphic
Red Shale
Lutite (primarily composed of Hydrous Aluminum Silicates with Hematite staining)
sedimentary
Fossil Coral
Phylum Cnidaria / Rugosa or Tabulata
fossil
Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Red Jasper
Red Jasper (variety of Chalcedony, SiO₂)
Mineral
Diamond
Carbon (C)
Mineral
Tumbled serpentine
Serpentinite; chiefly serpentine-group minerals, Mg3Si2O5(OH)4
metamorphic
Granite
Granite
igneous
Chert (Yellow/Brown variety)
Chert (SiO2)
sedimentary
Silver (Native or Alloyed)
Ag (Argentum)
mineral
Chert (Fossiliferous)
Silicon dioxide (SiO2)
sedimentary
Milky quartz with dark host-rock inclusions
Quartz (SiO₂), likely in a granitic or metamorphic matrix
mineral
Likely iron-rich slag or weathered ironstone
Hematite–goethite-rich material (Fe₂O₃/FeO(OH)); possibly industrial iron slag
mineral
Sandstone (Weathered)
Arenite (primarily SiO2)
sedimentary
Iron-stained milky quartz
Quartz (SiO₂), mainly massive or vein quartz, with reddish-brown iron-oxide staining and possible minor feldspar or other vein minerals
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3/FeO(OH) cementing agents)
sedimentary
Raw calcite specimen
Calcite, calcium carbonate (CaCO₃)
mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Sandstone
Arenite (SiO2 based with various mineral cements)
sedimentary
Sandstone
Arenite (SiO2 based)
sedimentary
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Tumbled green-brown stone, likely serpentine
Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite
metamorphic