Igneous Or Sedimentary (Anthropogenic Modification)

Banded gneiss

Foliated gneiss, likely quartz–feldspar–mica gneiss

Gneiss

Gneiss (High-grade Metamorphic Rock)

Banded metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss (probable); exact identification requires testing

Banded gneiss pebble

Gneiss, likely quartz–feldspar–mica gneiss

Gneissic River Cobble

Gneiss

Gneiss

Gneiss (High-grade metamorphic rock)

Gneiss (specifically a Hornblende Gneiss or Micaceous Gneiss)

Gneiss (metamorphic rock composed primarily of quartz, feldspar, and mafic minerals)

Agate Geode with Quartz Druzy

Cryptocrystalline Quartz (SiO2)

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Banded gneiss

Gneiss, commonly quartz–feldspar–mica gneiss

Gneiss

Metamorphic Gneiss (High-grade regional metamorphism)

Weathered gneissic rock

Biotite–quartz–feldspar gneiss, possibly migmatitic

Banded Gneiss

Gneiss (quartz-feldspar-biotite metamorphic rock)

Uncertain gray metamorphic rock, likely gneiss or schist

Quartz–feldspar–mica rock; exact identification requires close examination

Greenstone (Greywacke or Nephrite Jade variant)

Metamorphosed mafic igneous or sedimentary rock (e.g., Actinolite-Chlorite Schist)

River Pebble (Gneiss/Schist mix)

Metamorphic rock aggregate

Botryoidal Chalcedony (Agate)

Silicon Dioxide (SiO2)

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Gneiss with Quartz/Feldspar Vein

Quartz-Feldspathic Gneiss

Gneiss

Gneiss

Banded Gneiss (with Quartz Vein)

Gneiss (SiO2 and varied Silicates)

Gneiss (Banded Gneiss)

Gneiss

Granite / Gneiss (Felsic Metamorphic or Igneous Rock)

Gneiss (or weathered Granite)

Banded gneiss (likely weathered paragneiss)

Gneiss; quartz–feldspar–mica ± amphibole assemblage

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Banded Gneiss

Gneiss (Metamorphic Rock)

Gneiss

Foliated Metamorphic Gneiss

Banded Agate (Agatized Geode Slice)

Silicon Dioxide (SiO₂)

Gneiss

Gneiss

Gneiss (High-Grade Metamorphic Rock)

Gneiss (primarily composed of Quartz, Feldspar, and Mica/Amphiboles)

Gneiss (with Quartzite and Mica)

Gneiss

Jasper

Silicon dioxide (SiO2)

Gneiss

Gneiss

Gneiss (Banded Gneiss)

Gneiss

Banded gneiss pebble

Gneiss, chiefly quartz–feldspar–mica with dark biotite/amphibole bands

Polished banded gneiss

Biotite–quartz–feldspar gneiss, locally migmatitic

Gneiss

Gneiss (High-grade metamorphic rock)

Banded Agate

Chalcedony (SiO2) with impurities

Quartz Geode

Silicon Dioxide (SiO2)

Quartz Geode

Quartz (Silicon Dioxide, SiO2)

Banded Agate (specifically Sardonyx or Carnelian Agate)

Silicon Dioxide (SiO2) - Chalcedony variety

Banded Gneiss with Quartz Vein

Foliated Metamorphic Rock (Gneiss)