Granite or granitic gneiss boulders
Quartz–feldspar–mica granitoid; possibly banded gneiss
igneous
Category
Rock
Browse rock specimens identified by the Rock Identifier community.
Granite with Cupules / Bedrock Mortars
Granite (felsic intrusive plutonic rock)
igneous
Sandstone
Sedimentary Rock (Quartz Arenite)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Quartzite with Hematite staining
Quartzite (SiO2) with iron oxide inclusions
metamorphic
Halite
Sodium Chloride (NaCl)
mineral
Schist
Metamorphic Schist
metamorphic
Coal
Carbonaceous sedimentary rock / Lignite to Bituminous coal
sedimentary
Pyrite-bearing Rock / Pyrite Ore
Iron Sulfide (FeS2) in host rock matrix
mineral
Quartzite (River Pebble)
Meta-quartzite (composed primarily of SiO2)
metamorphic
Sandstone
Sedimentary Rock
sedimentary
Conglomerate
Conglomerate rock
sedimentary
Sandstone
Sedimentary Rock
sedimentary
Sandstone or Mudstone
Sedimentary Rock
sedimentary
Conglomerate
Conglomerate Rock
sedimentary
Conglomerate
Conglomerate Rock
sedimentary
Porphyry
Porphyritic Rock
igneous
Conglomerate
Conglomerate rock
sedimentary
Rounded, weathered metamorphic rock (likely quartz-rich gneiss or schist)
Undetermined; likely quartz–feldspar-rich gneiss, with possible mica and iron-oxide staining
metamorphic
Sandstone (likely Greywacke or Lithic Sandstone)
Arenite / Wacke
sedimentary
Biotite-bearing granite
Granite, composed chiefly of quartz, feldspar, and biotite; exact identification is uncertain from the photo.
igneous
Feldspathic gneiss (likely augen gneiss)
Quartz–feldspar–mica gneiss; commonly dominated by quartz, K-feldspar/plagioclase, and biotite
metamorphic
Granite fragment (tentative)
Granite; primarily quartz (SiO₂), feldspar, and mica
igneous
Granite / granitic gneiss boulders
Granite, primarily quartz, feldspar, and mica; some pieces may be foliated granitic gneiss
igneous
Light-colored granite or granitic gneiss
Granite; typically quartz + feldspar + mica (variable composition)
igneous
Dark gray-brown stone, likely basalt or fine-grained volcanic rock
Basalt (tentative; likely plagioclase–pyroxene rock)
igneous
Rounded gray river pebble, likely basalt or andesite
Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase ± pyroxene/olivine)
igneous
River Cobble (Weathered Granitoid)
Granodiorite / Quartz Diorite
igneous
Shale with Quartz Veins
Fissile Sedimentary Rock (SiO2)
sedimentary
Granite
Intrusive Igneous Rock
igneous
Basalt Pebble
Extrusive Igneous Rock (Mafic)
igneous
Basalt
Extrusive mafic igneous rock
igneous
Breciated Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Hag Stone
Perforated Flint or Limestone
sedimentary
Brachiopod Fossil
Phylum Brachiopoda
fossil
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Fish Fossil in Limestone
Lycoptera (likely) in Micritic Limestone
sedimentary
Small polished agate (likely banded chalcedony)
Chalcedony, microcrystalline quartz (SiO₂)
mineral
Banded agate (likely botryoidal chalcedony)
Agate, microcrystalline quartz (SiO₂), commonly chalcedony with quartz bands
mineral
Sandstone with Iron Banding
Arenite with Hematite or Limonite staining (SiO2 with Fe2O3)
sedimentary
Red Sandstone
Arenite (Ferruginous Sandstone)
sedimentary
Greenish altered rock, possibly serpentinite or chlorite-rich schist
Tentative: serpentine-group minerals, chiefly antigorite/lizardite, or chlorite–actinolite assemblage
metamorphic