Igneous And Sedimentary

Banded Gneiss

Banded Orthogneiss or Paragneiss (Quartz-Feldspathic Gneiss)

Banded gneiss pebble

Gneiss, likely quartz–feldspar–mica gneiss

Banded metamorphic rock, likely gneiss

Gneiss; predominantly quartz–feldspar with mica/amphibole minerals

Dark gneiss or amphibolite cobble

Banded metamorphic rock, likely quartz–feldspar–biotite gneiss or amphibolite

Tumbled banded gneiss or amphibolite

Banded metamorphic rock, likely quartz–feldspar–biotite gneiss with amphibole

Gneiss

Gneiss

Foliated metamorphic rock, likely gneiss with amphibolite or chlorite-rich bands

Biotite–quartz–feldspar gneiss, locally mafic amphibolite; mineral composition is uncertain from the photograph

Garnet-bearing gneiss

Quartz–feldspar–mica gneiss with iron-rich garnet (commonly almandine)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Chalcedony (Carnelian Agate pebble)

Silicon Dioxide (SiO2)

Gneiss

Gneiss

Gneissic River Pebble

Gneiss

Gneiss (Banded Gneiss)

Gneiss

Turquoise (possible Dyed Magnesite/Howlite)

CuAl6(PO4)4(OH)8·4H2O

Gneiss

Gneiss

Agate Geode

Chalcedony (cryptocrystalline SiO2)

Gneiss

Metamorphic Gneiss (High-grade regional metamorphism)

Gneiss (River Cobble)

Metamorphic Gneiss

Banded gneiss pebble

Gneiss, commonly quartz–feldspar–mica gneiss

Banded gneiss (likely amphibolite-bearing gneiss)

Gneiss; quartz–feldspar–mica/amphibole aggregate

Banded metamorphic rock, likely gneiss or banded amphibolite

Quartz–feldspar–biotite gneiss or amphibolite; exact identification requires thin-section or mineral tests

Banded Gneiss

Gneiss (High-grade metamorphic rock)

Gneiss

Gneiss (Metamorphic Rock)

Banded gneiss pebble

Gneiss, chiefly quartz–feldspar–biotite (composition variable)

Banded gneiss

Gneiss, commonly quartz–feldspar–biotite gneiss

Banded gneiss

Gneiss, commonly quartz–feldspar–mica assemblage

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Gneiss

Gneiss (High-grade metamorphic rock)

Banded Gneiss (with Quartz Vein)

Gneiss (SiO2 and varied Silicates)

Gneiss

Gneiss

Quartz–feldspar–mica metamorphic rock, likely gneiss

Gneiss; composition commonly quartz (SiO₂), feldspars, biotite/hornblende, and minor accessory minerals

Garnet Amphibolite (or Garnet Gneiss)

Garnet amphibolite / Garnet-bearing metamorphic rock

Blue Chalcedony

Microcrystalline Quartz (SiO2)

Gneiss with Orthoclase Feldspar

Gneissic Metamorphic Rock with K-Feldspar inclusions

River Cobble (Salt and Pepper Gneiss)

Gneiss (High-grade regional metamorphic rock)

Gneiss

Gneiss

Gneiss (Metamorphic Pebble)

Gneissic Metamorphic Rock

Gneiss

Gneissic Metamorphic Rock

Gneiss (Metamorphic Rock)

Gneiss

Granite Gneiss River Rock

Gneiss

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Gneiss (Banded Gneiss)

Gneiss