Vesicular Basalt (Scoria)
Aphanitic Mafic Igneous Rock (Vesicular Basalt)
igneous
Category
Rock
Browse rock specimens identified by the Rock Identifier community.
Serpentine (Serpentinite)
Serpentinite / (Mg,Fe)3Si2O5(OH)4
metamorphic
Rounded gray river pebble, likely basalt or andesite
Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase ± pyroxene, possibly olivine)
igneous
Quartzite River Stone
Quartzite (SiO2)
metamorphic
Geode
Quartz / Chalcedony nodule
sedimentary
Mudstone
Argillite
sedimentary
Ferrous Slag (Iron Smelting By-product)
Fused Siliceous Slag
Anthropogenic Material (Man-made Rock)
Sandstone (Painted)
Arenite (primarily SiO2)
sedimentary
Quartzite Pebble
Metamorphic Quartzite (SiO2)
metamorphic
Gneiss (Pebble)
Gneiss
metamorphic
Brecciated Jasper
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary
Chert (Yellow/Tan Variety)
Chert (SiO2)
sedimentary
Serpentine (Serpentinite)
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
metamorphic
Vesicular Basalt
Extrusive mafic igneous rock
igneous
Grey Limestone Pebble
Limestone (Calcium Carbonate - CaCO3)
sedimentary
Basalt
Basalt (Mafic Extrusive Igneous Rock)
igneous
Slate with Quartz Vein
Foliated Metamorphic Rock (Mainly Quartz, Muscovite, Chlorite)
metamorphic
Conglomeratic gravel / lithified alluvial deposit
Polymictic conglomerate or pebble-rich sandstone (likely weakly cemented)
sedimentary
Sandstone (with Iron Staining)
Clastic sedimentary rock (SiO2 with Fe2O3 oxides)
sedimentary
Quartz Vein in Host Rock
Hydrothermal Quartz (SiO2) in Slates/Schists
metamorphic
Quartz Veined Basalt
Mafic Volcanic Rock with Microcrystalline Quartz (SiO2)
igneous
Brecciated quartz vein rock
Quartz (SiO₂), with iron-oxide staining and likely feldspar/carbonate gangue
mineral
Quartz vein in weathered host rock
Quartz (SiO₂), likely in a weathered metamorphic or igneous matrix
mineral
Banded Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Large rounded metamorphic boulder, likely gneiss or granitic gneiss
Gneiss (likely quartz–feldspar–mica gneiss; exact identification requires closer examination)
metamorphic
Granite
Granite; chiefly quartz, feldspar, and mica
igneous
Granite boulder
Granite; chiefly quartz, feldspar, and mica
igneous
Gneiss, likely migmatitic or granitic gneiss
Banded quartz–feldspar–mica gneiss; composition chiefly quartz, alkali/plagioclase feldspar, biotite and accessory minerals
metamorphic
Polished banded gneiss
Biotite–quartz–feldspar gneiss, locally migmatitic
metamorphic
Weathered granite fragment
Granite, primarily quartz, feldspar, and mica
igneous
Quartz Vein in Basalt or Slate
Hydrothermal quartz vein traversing mafic host rock
metamorphic
Druzy Quartz on Chert/Siltstone
Silicon Dioxide (SiO2) on Microcrystalline Silica/Siltstone matrix
sedimentary
Quartz (Druzy)
Silicon Dioxide (SiO2)
mineral
Flagstone (likely sandstone or slate)
Flagstone is a paving form, not a single rock species; likely thin-bedded sandstone, with possible slate pieces
sedimentary
Milky Quartz
Quartz (Silica / Silicon Dioxide), SiO2
mineral
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Granite
Intrusive Igneous Rock
igneous
Iron-stained rock fragment, possibly quartz-rich
Unidentified quartz-rich rock with iron-oxide staining (likely hematite/goethite)
mineral
Quartz vein in dark host rock
Quartz (SiO₂), likely in basalt, gabbro, or altered mafic rock
mineral
Shale
Fissile mudrock (composed of clay-sized particles and detrital grains)
sedimentary
Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Serpentine (likely greenstone)
Serpentine-group minerals, chiefly antigorite, lizardite, and chrysotile; commonly with magnesite or magnetite
metamorphic