Unidentified weathered rock fragment
Likely granitic or feldspathic rock; exact identification requires clearer imaging and testing
Category
Browse antropogenic (man made glass byproduct) specimens identified by the Rock Identifier community.
Unidentified weathered rock fragment
Likely granitic or feldspathic rock; exact identification requires clearer imaging and testing
Green aventurine cabochon (likely)
Quartzite/aventurine quartz, predominantly SiO₂ with possible fuchsite mica
Black-and-white gneiss
Gneiss, chiefly quartz–feldspar with dark biotite/amphibole bands
Flint or chert flake
Microcrystalline quartz (SiO₂), commonly chert/flint
Sandstone
Sedimentary Clastic Rock
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Sandstone Pebble
Sedimentary Clastic Rock (Quartz Arenite)
Quartz
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)
Feldspar (Plagioclase / Potassium Feldspar)
Feldspar Group (KAlSi3O8 - NaAlSi3O8 - CaAl2Si2O8)
Milky Quartz
Silicon Dioxide (SiO2)
Sandstone (Iron-stained)
Arenite (primarily SiO2 with Fe2O3 staining)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
Sandstone
Arenite (SiO2 primarily)
Sandstone
Arenite (primarily SiO2)
Milky Quartz with Chlorite/Mica inclusions
Silicon Dioxide (SiO2) with inclusions
Quartzite pebble
Quartzite (SiO2)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Rough Apatite in Matrix
Fluorapatite / Chlorapatite / Hydroxylapatite (Ca5(PO4)3(F,Cl,OH))
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz (Gray or Smoky variety)
Silicon Dioxide (SiO2)
Quartzite Pebble
Metamorphic rock predominantly composed of Quartz (SiO2)
Diamond (or diamond simulant)
C
Granite (Gneissic / Weathered Pebble)
Felsic intrusive igneous rock (Granite)
Black basalt (likely polished or cut fragment)
Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase, clinopyroxene, and often olivine or magnetite
Tumbled pink granite or feldspar-rich granitic pebble
Granite, composed mainly of quartz, potassium feldspar, and plagioclase; exact identification is uncertain from the image
Limestone
Calcium Carbonate (CaCO3)
Limestone (with potential fossil inclusions)
Calcium Carbonate (CaCO3)
Granite
Phaneritic Plutonic Felsic Rock (SiO2 > 69%)
Limestone (Grey and White specimens)
Calcium Carbonate (CaCO3)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Polished agate/chalcedony fragment
Microcrystalline quartz (SiO₂), likely banded chalcedony or agate
River Stone (Limestone)
Sedimentary Calcium Carbonate (CaCO3)
Granite
Granite (Felsic Plutonic Rock)
Limestone
Calcium Carbonate (CaCO3)
Granite
Granite (Felsic Plutonic Rock)
Granite
Phaneritic Igneous Rock (Granite)