Chert (Flint)
Silicon Dioxide (SiO2)
Category
Browse man made rock (sedimentary analogue) specimens identified by the Rock Identifier community.
Chert (Flint)
Silicon Dioxide (SiO2)
Mixed polished gemstone and mineral collection
Primarily quartz varieties (SiO₂), plus probable aventurine, rose quartz, amethyst, agate, jasper, serpentine, feldspar, and possibly dyed or man-made glass pieces
Sandstone (Water-worn Cobble)
Arenite (SiO2 with CaCO3 or Fe2O3 cement)
Chert (Flint)
Silicon dioxide (SiO2)
Slate
Metamorphic Pelitic Rock
Blue slag glass or dyed glass-like industrial material
Amorphous silicate glass; likely copper-bearing blue slag, but possibly colored man-made glass
Sandstone
Sedimentary Clastic Rock (Quartzose Sandstone)
Slag Glass (Leland Blue variant)
Anthropogenic Vitreous Silicate
Sandstone
Sandstone (clastic sedimentary rock, predominantly SiO2)
Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
Chert (Flint)
SiO2 (Microcrystalline Quartz)
Banded Gneiss
Gneiss (Foliated Metamorphic Rock)
Coquina / Fossiliferous Limestone
Calcareous bioclastic sedimentary rock (CaCO3)
Tumbled black obsidian (likely)
Volcanic glass; chiefly silica-rich rhyolitic glass (SiO₂)
Glass / Silicon Dioxide (Man-made)
SiO2 (Amorphous Silicon Dioxide)
Chert (Flint)
Microcrystalline quartz (SiO2)
Asphalt aggregate (crushed stone in bitumen)
Artificial composite; predominantly crushed granite, basalt, limestone, and/or recycled aggregate bound by bitumen
Green Agate
Silicon dioxide (SiO₂)
Red Sandstone
Quartz Arenite (iron-stained) / SiO2
Chert Arrowhead
Cryptocrystalline Quartz (SiO2)
Sandstone (specifically Arkose or Quartz Arenite)
Arenite (primarily SiO2 with possible Feldspar)
Limestone
Calcareous sedimentary rock (CaCO3)
Man-made Glass (Tumbled/Shaped)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Man-made Crystal (Lead Glass)
Lead oxide-doped Silica Glass (approx. SiO2 + PbO)
Man-made Dyed Aura Quartz
Silicon Dioxide (SiO2) with metallic coating/dye
Concrete or asphalt-like aggregate surface with a dark fragment
Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock
Sandstone (Pebble)
Arenite
Sandstone
Arenite
Blue sea glass or blue glassy mineral fragment
Uncertain; likely man-made soda-lime glass, not a natural mineral
Blue glassy fragment among beach gravel
Likely cobalt-blue man-made glass; not a natural mineral specimen
Opalite
Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)
Slag Glass (Cullet)
Amorphous Silica (man-made), primarily SiO2 with trace metal oxides
Fossilized Coral (Coquina/Limestone)
Cnidaria Anthozoa (Fossilized)
Libyan Desert Glass
Impact-melt silica glass (SiO2 + traces of Al, Fe, Ti)
Weathered concrete or cementitious slab (not natural rock)
Artificial calcium-silicate cement composite; likely Portland cement concrete
Asphalt Chunk (with aggregate)
Bituminous concrete / Anthropogenic conglomerate
Swirled Agate Bead
Silicon Dioxide (SiO2)
Chert (often called Flint)
Chert (Microcrystalline or cryptocrystalline Silica, SiO2)
Sandstone
Arenite
Chalcedony (Agate/Chert variety)
Silicon Dioxide (SiO2)
Chert
Microcrystalline Quartz (SiO2)
White pebbles (rock material not identifiable from the image)
Undetermined; the smooth, pale pieces could be quartz, quartzite, or another light-colored rock