Igneous Or Sedimentary

Epidote with Magnetite/Hematite inclusions

Epidote (Ca2(Al2,Fe3+)(SiO4)3(OH)) with Iron Oxides

Gneiss (rounded cobble)

Quartz–feldspar–mica gneiss; exact mineral proportions cannot be determined from the image

Banded gneiss

Gneiss, commonly quartz–feldspar–mica gneiss

Worn quartz-rich pebble

Likely microcrystalline quartz (SiO₂), possibly a weathered chert or milky quartz fragment

Banded Gneiss

Metamorphic Gneiss (High-grade regional metamorphism specimen)

Gneiss (High-grade Metamorphic Rock)

Gneiss (Metamorphic silicate rock)

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Carnelian

Carnelian (SiO2, Silicon Dioxide with Iron Oxide impurities)

Gneiss (specifically a Banded Gneiss cobble)

Gneiss (composed mainly of Quartz, Feldspar, and Biotite/Amphibole)

Banded gneiss pebble

Gneiss, commonly quartz–feldspar–biotite gneiss

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Quartz Druze on Matrix (Geode Fragment)

Quartz (Silicon Dioxide, SiO2)

Gneiss (probable)

Quartz–feldspar–mica gneiss; exact mineral composition cannot be confirmed from the image

Gneiss

Gneiss (High-grade Metamorphic Rock)

Gneiss

Gneiss

Banded metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss, possibly amphibolite-bearing

Banded Gneiss

Gneiss (Metamorphic Rock)

Banded Gneiss

Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica)

Amethyst

Amethyst (Silicon Dioxide - SiO2 with iron impurities)

Specular Hematite

Hematite (Fe2O3)

Banded Gneiss and Siltstone River Stones

Gneiss (High-grade Metamorphic Rock)

Gneiss (Schistose)

Gneiss

Carnelian

Carnelian (Silicon Dioxide - SiO2)

Carnelian

Cryptocrystalline Quartz (SiO2 with iron oxide impurities)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Bloodstone Jasper (Heliotrope)

SiO2 (Silicon Dioxide) - Cryptocrystalline Quartz

Labradorite-bearing gneiss or schist

Feldspathic gneiss/schist containing iridescent labradorite (plagioclase feldspar, NaAlSi₃O₈–CaAl₂Si₂O₈)

Banded Gneiss

Gneiss (High-grade metamorphic rock)

Gneiss

High-grade Metamorphic Gneiss

Polished banded gneiss

Biotite–quartz–feldspar gneiss, locally migmatitic

Polished pale chalcedony or quartz pebble

Microcrystalline quartz, SiO₂; possibly milky quartz/chalcedony

Gneiss

Gneiss

Banded gneissic rock

Gneiss, likely quartz–feldspar–biotite gneiss

Gneiss

Metamorphic Gneiss

Banded gneiss (possibly migmatitic gneiss)

Quartz–feldspar–mica gneiss; composition commonly includes quartz, feldspar, biotite/hornblende, and accessory dark minerals

Gneiss

Quartz–feldspar–mica gneiss

Foliated Gneiss (River-Worn Pebble)

Gneiss (High-grade Regional Metamorphic Rock)

Quartz Geode (Nodule)

Silicon Dioxide (SiO2)

Tree Agate

Dendritic Agate (Silicon Dioxide, SiO2)

Banded gneiss

Foliated quartz–feldspar gneiss, likely biotite-bearing

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Feldspathic Gneiss

Feldspathic Gneiss (High-grade regional metamorphic rock)