Metamorphic (Likely Gneiss Or Schist Based On Texture)

Granitic Gneiss

Gneiss (Metamorphic rock of granitic composition)

Quartzite with Mica / Gneiss Pebble

Metamorphic Rock (Quartz-Feldspar-Mica aggregate)

Muscovite Schist

KAl2(AlSi3O10)(OH)2 (Muscovite) in Schist Matrix

Gneiss Pebble

Gneiss

Gneiss

Gneiss (High-grade metamorphic rock)

Banded Gneiss (River Cobble)

Gneiss (a high-grade metamorphic rock)

Weathered granitic gneiss (probable)

Quartz–feldspar–biotite gneiss; compositionally similar to granite

Mica Schist

Mica Schist (primarily Muscovite or Biotite KAl2(AlSi3O10)(OH)2)

Likely weathered metamorphic rock (quartzite or schist)

Quartz-rich foliated metamorphic rock; exact identification requires testing

Mica Schist (with Muscovite)

Muscovite/Quartz Schist (KAl2(AlSi3O10)(OH)2)

Banded Rock (likely Quartz-rich)

Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals

Gneiss

Metamorphic rock (Gneiss)

Sandstone (likely Calcareous or Quartz-rich)

Arenite (SiO2 based typically)

Granitic Gneiss

Gneiss (Metamorphic rock predominantly containing quartz, K-feldspar, and plagioclase)

Gneiss

Orthogneiss / Paragneiss

Corundum (Ruby variety)

Aluminium oxide (Al2O3)

Almandine Garnet in Matrix

Almandine Garnet (Fe3Al2(SiO4)3)

Mica Schist with Quartz

Mica Schist (primarily Muscovite or Biotite with Quartz)

Banded Gneiss

Gneiss (High-grade metamorphic rock)

Rounded gray metamorphic cobble, likely quartzite or gneiss

Quartz-rich metamorphic rock; possibly quartzite (mostly SiO₂) or banded gneiss

Sandstone (Quartz Sandstone)

Arenite (SiO2 based)

Ruby (in costume jewelry context)

Corundum (Al2O3) with Chromium impurities

Gneiss

Metamorphic Gneiss (High-grade regional metamorphism)

Greenschist / Chloritaform Schist

Chlorite Schist (Group of Silicate Minerals)

Gneiss

Gneiss (High-grade metamorphic rock)

Mica Schist

Mica Schist (primarily Muscovite and Quartz)

Schist

Schist (Metamorphic Rock)

Ruby (Corundum)

Corundum (Aluminum Oxide with Chromium), Al2O3:Cr

Gneiss Pebble

Gneiss (High-grade metamorphic rock)

Schist

Mica Schist

River Cobble (Salt and Pepper Gneiss)

Gneiss (High-grade regional metamorphic rock)

Greenschist

Greenschist (Actinolite-Chlorite Schist)

Quartz (likely) / Siliceous rock with quartz phenocrysts (if a rock fragment)

Quartz (SiO₂)

Orange Quartzite / Carnelian Agate

Silicon Dioxide (SiO2)

Gneiss

High-grade Metamorphic Gneiss

Greenschist

Chlorite schist

Graphite

Graphite (Carbon, C)

Sandstone (Quartzose)

Arenite (SiO2 based typically)

Staurolite (Fairy Cross)

Staurolite (Fe2+2Al9Si4O23(OH))

Garnet (Almandine or Spessartine likely)

Garnet Group Minerals (e.g., Almandine Fe3Al2(SiO4)3, Pyrope Mg3Al2(SiO4)3, Spessartine Mn3Al2(SiO4)3)

Mica Schist fragment

Mica Schist (KAl2(AlSi3O10)(OH)2 / K(Mg,Fe)3(AlSi3O10)(OH)2)

Muscovite Schist

Mica Schist (primarily KAl2(AlSi3O10)(OH)2)