Metamorphic Or Igneous (Context Dependent)

River Cobble (Gneiss/Migmatite)

Gneissic Metamorphic Rock (composed mainly of Quartz, Feldspar, and Biotite)

Gneiss (High-grade Metamorphic Rock)

Gneiss (Metamorphic silicate rock)

Biotite Schist

Biotite-rich Schist

Gneiss (Granitic Gneiss)

Gneiss (composed mainly of quartz, K-feldspar, plagioclase, and biotite)

Banded Gneiss

Gneiss (Metamorphic rock predominantly containing quartz, feldspar, and mica)

Gneissic Granite (River Stone)

Protomylonite or Gneiss

Greenstone

Metabasalt (Greenstone)

Greenschist

Greenschist (Chlorite Schist facies)

Greenstone (Metabalt)

Chlorite schist / Altered Basalt

Gneiss

Gneiss

Gneiss

Gneiss

Gneiss (with Quartzite and Biotite)

Gneiss containing SiO2 (Quartz), K(Mg,Fe)3AlSi3O10(OH)2 (Biotite), and (K,Na,Ca)AlSi3O8 (Feldspar)

Greenstone / Greenstone Pebble

Greenschist (metamorphosed basalt or gabbro)

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Banded Gneiss

Foliated Gneiss

Greenstone or Chlorite Schist

Greenschist / Chlorite schist

Gneiss

Gneiss

Gneiss

Gneiss

Nuummite

Antophyllite-Gedrite Orthoamphibole (Mg,Fe)7Si8O22(OH)2

Gneiss

Gneiss

Greenstone (Prase / Metavolcanic)

Metamorphosed volcanic rock (Greenstone)

Beach Pebble Quartzite / Chalcedony Pebble

Silicon Dioxide (SiO2)

Greenstone (Greenschist facies)

Greenschist (composed primarily of Chlorite, Actinolite, and Epidote)

Gneiss

Gneiss

Gneiss (Banded Gneiss)

Gneiss

Granite Gneiss

Felsic Gneiss (composed of Quartz, Feldspar, and Biotite)

Gneiss

Gneiss (Metamorphic rock composed primarily of Quartz, Feldspar, and Mica/Amphibole)

Greenstone

Greenschist / Greenstone (containing Chlorite, Epidote, Actinolite)

Gneiss (with Quartz and Biotite Mica)

Gneiss

Banded Gneiss

Gneiss

Greenstone

Greenschist / Meta-basalt

Gneiss

Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)

Garnet Gneiss

Gneiss containing almandine-pyrope garnet

Gneiss

Gneiss

Gneiss

Gneiss

Greenstone (Epidosite or Serpentinite)

Metabasalt / Epidote-Chlorite Schist

Mixed rounded river pebbles, likely basalt and granite

Basalt (fine-grained mafic rock) and granite/granitoid (quartz–feldspar rock)

Dark gray volcanic rock, probably andesite or basalt

Fine-grained mafic–intermediate volcanic rock; likely basalt (plagioclase ± pyroxene), possibly andesite

Polished river pebble, likely granite or granitic gneiss

Quartz–feldspar–mica aggregate; possibly biotite granite (compositionally near granite)

Gneiss

Gneiss (Metamorphic high-grade)

Gneiss (River Cobble)

Gneiss (Foliated Metamorphic Rock)

Tumbled white quartz pebble

Quartz (silicon dioxide, SiO₂)