Asphalt Chunk
Asphalt concrete
Category
Browse synthetic polymer (synthetic material) specimens identified by the Rock Identifier community.
Asphalt Chunk
Asphalt concrete
Limestone
Calcium Carbonate (CaCO3)
Garnet Schist
Garnetiferous Mica Schist
Sandstone
Arenite (primarily SiO2)
Coquina or Fossiliferous Limestone
Fossiliferous Calcarenite (CaCO3)
Jasper / Chert (Red)
Cryptocrystalline quartz (SiO2)
Fossil bivalve shell
Likely an extinct or modern-like ribbed cockle/scallop; exact genus requires locality and diagnostic hinge features
Coquina
Bioclastic Limestone
Sandstone
Arenite (primarily SiO2 with Fe2O3)
Vesicular volcanic rock, likely weathered pumice or scoria
Pumice/scoria; predominantly volcanic glass and feldspar, with possible iron oxides
Banded Calcite (often sold as Mexican Onyx or Aragonite)
Calcite/Aragonite (Calcium Carbonate, CaCO3)
N/A - Image does not contain a rock or mineral
Anthropogenic textile material
Ferrochrome Slag
Calcium-Aluminium-Magnesium Silicate Slag
Petrified Wood (Jet or Coalified Wood appearance)
Silicified wood (principally SiO2) or Carbonized Wood
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)
Rough amethyst-bearing quartz specimens
Quartz, SiO₂; purple coloration from trace iron and irradiation
Rhyolitic Tuff
Rhyolitic Tuff / Pyroclastic rock
Polished green-and-white stone, likely serpentine or nephrite jade
Serpentine-group minerals, commonly antigorite/lizardite; possible nephrite (interlocking actinolite–tremolite)
Gravel / Crushed Stone
Aggregate (mixed mineral rock fragments)
Serpentine
Hydrous magnesium iron silicate, (Mg,Fe)3Si2O5(OH)4
Limestone
Calcite (CaCO3)
Vesicular volcanic rock, likely scoria
Scoria; composition commonly basaltic to andesitic, rich in plagioclase and pyroxene
Quartzite
Quartzite (SiO2)
Coquina
Biogenic Limestone (Calcium Carbonate, CaCO3)
Polished Mexican “Crazy Lace” agate tower
Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions
Diamond (or Simulant)
Carbon (C) or relevant simulant formula (e.g., ZrO2 for Cubic Zirconia)
Likely basalt pebble
Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene with possible olivine
Limestone
Calcium Carbonate (CaCO3)
Pink Quartzite
Quartzite (principally Silicon Dioxide, SiO2)
Laterite (Iron-rich bauxite or Gossan)
Ferricrete (Fe2O3·nH2O)
Coquina
Biogenic Limestone (mostly Calcium Carbonate, CaCO3)
Tumbled or rough turquoise-like specimen
Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O; identification is uncertain from the image
Nephrite Jade
Nephrite
Brecciated jasper/chert
Microcrystalline quartz (SiO₂), with iron-oxide and clay inclusions
Petrified Wood
Silicified Wood (SiO2)
Quartz
Silicon Dioxide (SiO2)
Sandstone
Arenite (Clastic Sedimentary Rock)
Basaltic Tuff / Volcanic Breccia
Pyroclastic Breccia / Lithic Tuff
Sandstone
Arenite (primarily Quartz, SiO2)
Coal (Bituminous / Anthracite)
Carbonaceous Sedimentary Rock (C)
Red Sandstone
Arenite (SiO2 with Fe2O3)
Sandstone
Arenite (composed primarily of SiO2)