Rounded granite or granitic gneiss pebble
Granite, chiefly quartz, feldspar, and mica; exact identification requires testing
igneous
Category
Rock
Browse rock specimens identified by the Rock Identifier community.
Quartz (Clear/Smoky Geode fragment)
Silicon Dioxide (SiO2)
mineral
Basalt (River Rock)
Basalt
igneous
Fossilized Shell Impression / Siltstone Fossil
Bivalvia / Brachiopoda mold in Siltstone
fossil
Granodiorite (Weathered)
Granodiorite
igneous
Fossil Coral
Rugose Coral or Tabulate Coral (Phylum Cnidaria)
fossil
Geode with Quartz and possibly Jasper/Hematite
Quartz (SiO2) and Chalcedony (cryptocrystalline SiO2), possibly stained by iron oxides
Mineral/Sedimentary Geode
Granite
Intrusive Igneous Rock
igneous
Chert with Quartz Veining
Microcrystalline Silica (SiO2)
sedimentary
Granite
Granite (Phaneritic Quartz-Feldspar Plutonic Rock)
igneous
Quartz Geode
Quartz (Silicon Dioxide, SiO2)
mineral
Vesicular Basalt (Scoria)
Basalt with vesicular texture
igneous
Basalt Pebble (Vesicular / Beach Cobble)
Basalt (mafic extrusive igneous rock)
igneous
Jasper
Silicon dioxide (SiO2)
mineral
Granite / Quartzite Specimen
Granite / Quartz (SiO2 with Feldspar and Mica)
igneous
Chert Pebble
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Yellow Quartzite (River Pebble)
Quartzite (SiO2)
metamorphic
Granite
Granite
igneous
Basalt
Extrusive igneous rock
igneous
Basalt with inclusion
Basalt (Aphanitic-Porphyritic texture)
igneous
Basalt with Scoria
Amygdaloidal Basalt / Vesicular Basalt
igneous
Druzy Quartz on Chert/Chalcedony
Silicon Dioxide (SiO2)
mineral
Weathered granite or granitic gneiss
Granite; predominantly quartz, feldspar, and mica (exact identification is uncertain from the image)
igneous
Granite-like igneous rock
Likely medium-grained granite or granodiorite; quartz–feldspar–mica aggregate
igneous
Unidentified dark gray rock fragment
Likely fine-grained basalt or andesite; exact identification requires testing
igneous
River Rock with Quartz Vein
Basalt or Andesite with Quartz Veining
igneous
Granite Cobble
Phaneritic Felsic Igneous Rock
igneous
Granite
Felsic intrusive igneous rock
igneous
Granite
Felsic intrusive igneous rock
igneous
Calcite (or Travertine / Limestone)
Calcium Carbonate (CaCO3)
sedimentary
Diorite
Intermediate plutonic igneous rock
igneous
Granite
Granite (composed primarily of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase)
igneous
Banded Iron Formation (Fragment)
Banded Iron Formation (BIF)
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Sandstone
Clastic sedimentary rock (Quartz arenite or arkose)
sedimentary
Basalt
Basalt (Mafic volcanic rock)
igneous
Asphalt Chunk (with aggregate)
Bituminous concrete / Anthropogenic conglomerate
sedimentary (anthropogenic/man-made conglomerate)
Crushed Granite and Basalt
Phaneritic Igneous Rock / Aphanitic Igneous Rock
igneous
Iron-rich breccia or weathered ironstone
Goethite–hematite-bearing limonite, possibly with quartz and altered rock fragments
igneous
Unidentified Rock Fragment
Unknown
Rock
Rounded gray river pebble, likely fine-grained basalt or andesite
Basaltic-andesitic volcanic rock; commonly plagioclase feldspar, pyroxene, and minor iron oxides
igneous
Basalt
Aphanitic Mafic Volcanic Rock
igneous