Migmatite
Migmatite (Mixed metamorphic-igneous rock)
metamorphic
Category
Rock
Browse rock specimens identified by the Rock Identifier community.
Rounded river pebble
Lithic sandstone or fine-grained volcanic/metamorphic pebble; exact identity requires testing
sedimentary
Basalt with Quartz Veins
Aphanitic Mafic Igneous Rock (Main body: SiO2, Fe, Mg rich)
igneous
Unakite
Epidote-Feldspar rock
Metamorphic Rock
Unidentified pale mineral or rock surface
Indeterminate from image; possibly a small quartz or feldspar grain
mineral
Unakite
Unakite (altered granite containing Epidote, Orthoclase, and Quartz)
metamorphic
Veined Quartzite / Vein-filled Sedimentary Rock
Siliciclastic rock with iron oxide-filled fractures
sedimentary
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 oxides)
sedimentary
Polished moss agate (likely)
Chalcedony, microcrystalline SiO₂, with included green minerals such as chlorite or hornblende
gemstone
Polished banded agate (probable)
Microcrystalline quartz, SiO₂ (chalcedony/agate)
mineral
Agate (Water-Worn)
Cryptocrystalline quartz (SiO2)
sedimentary
Tumbled quartz-rich pebble
Quartz (SiO₂), likely a rounded quartzite or quartz-rich sandstone pebble
sedimentary
Tumbled green aventurine (probable)
Quartzite composed chiefly of quartz (SiO₂), with green fuchsite or other mica inclusions
mineral
Moonstone
Orthoclase Feldspar (KAlSi3O8)
mineral
Sandstone
Arenite (SiO2 based)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) within a geode
mineral
Basalt
Extrusive Igneous Rock
igneous
Unidentified small rocks or gravel
sedimentary
Quartz Vein in Basalt or Mafic Rock
Silicon Dioxide (SiO2) vein in volcanic/mafic matrix
igneous
Quartz-veined Basalt or Limestone Pebble
Quartz vein in host rock (Silicate mineral in carbonate or volcanic matrix)
sedimentary
Clear Quartz (Rock Crystal) Bracelet
Silicon Dioxide (SiO2)
gemstone
Painted Rock / Geode Specimen
Silicon Dioxide with artificial pigment coating
mineral
Gravel and Sand Aggregate
Unconsolidated Clastic Sediment
sedimentary
Starfish Fossil
Asteroidea fossil
fossil
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Druzy Quartz on Host Rock
Silicon Dioxide (SiO2)
mineral
River Rock (Basalt or Sandstone)
Clastic Sedimentary Rock or Extrusive Mafic Igneous Rock
igneous or sedimentary
Granite
Intrusive Igneous Rock
igneous
Granite
Intrusive Igneous Rock
igneous
Likely polished basalt or iron-rich metamorphic rock
Basaltic rock, chiefly plagioclase and pyroxene; exact identification requires testing
igneous
Sandstone (Lithic Wacke)
Clastic sedimentary rock (primarily SiO2 with rock fragments)
sedimentary
River Pebble (likely Quartzite or Diorite)
Metamorphosed Quartz-rich Rock / Intermediate Igneous Rock
metamorphic
River Rocks (Basalt and Sedimentary Stones)
Mafic Igneous Rock (Basalt) and Clastic Sedimentary Rock
igneous and sedimentary
Vesicular Basalt
Basalt with vesicular texture
igneous
Pink Granite
Phaneritic Felsic Igneous Rock (Granite, rich in Potassium Feldspar)
igneous
Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Basalt with Quartz Veins
Mafic Igneous Rock (primarily Plagioclase and Pyroxene) with SiO2 inclusions
igneous
Desert Varnish (on Sandstone)
Rock Varnish (composed of Manganese oxides, Iron oxides, and Clay minerals)
sedimentary
Basalt
Basalt
Igneous
Tumbled leopard-skin jasper (probable)
Orbicular rhyolite/jasper; primarily microcrystalline quartz (SiO₂) with feldspar and iron-oxide inclusions
igneous
Banded Sandstone
Arenite (with iron oxide banding)
sedimentary
Sandstone (Wonderstone)
Arenite (composed primarily of SiO2 with Fe2O3 impurities)
sedimentary