Mineral In Metamorphic Rock

Biotite-rich gneiss (possibly mica schist)

Quartz–feldspar–biotite gneiss; mica-rich metamorphic rock

Greenstone, likely altered basalt

Metabasalt (chlorite–actinolite–epidote assemblage), likely greenschist-facies greenstone

Mica Schist

Mica Schist (Quartz-Mica Metamorphic Rock)

Schist

Metamorphic Rock (Schist)

Banded gneiss pebble

Gneiss, commonly quartz–feldspar–mica gneiss

Schist

Metamorphic rock (Schist)

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, possibly with feldspar and mica impurities

Weathered iron-rich metamorphic rock, likely schist or phyllite

Quartz–mica schist/phyllite; composition likely quartz, mica, feldspar, and iron oxides

Likely biotite-rich metamorphic rock (mica schist)

Mica schist, chiefly quartz + biotite mica; possible pyrite or sulfide grains

Layered dark metamorphic rock, likely slate or phyllite

Slate/phyllite; predominantly fine-grained quartz, mica, and chlorite

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline quartz (SiO₂), possibly with mica, feldspar, and iron-oxide staining

Weathered mafic metamorphic rock, likely amphibolite

Amphibolite; chiefly hornblende amphibole and plagioclase feldspar, with minor biotite, quartz, or garnet

Banded Slate

Slate (Metamorphosed Siltstone/Mudstone)

Banded gneiss

Gneiss, commonly quartz–feldspar–mica gneiss

Garnet-bearing metamorphic rock, likely garnet schist or amphibolite

Almandine garnet (Fe₃Al₂Si₃O₁₂) in mica- or amphibole-rich matrix

Schist

Mica Schist

Galena-bearing metamorphic rock (tentative)

Likely galena (PbS) with quartz and/or carbonate matrix; exact identification requires testing

Dark gray foliated metamorphic rock, likely slate or phyllite

Slate–phyllite; predominantly quartz, mica, and chlorite

Quartz-bearing metamorphic rock, likely quartzite with dark mica/amphibole

Quartzite or quartz-rich schist; chiefly SiO₂ quartz with biotite, hornblende/amphibole, and iron-oxide staining

Foliated metamorphic rock, likely slate or phyllite

Slate–phyllite; composition commonly quartz, mica, and chlorite

Quartz-bearing metamorphic rock, likely quartzite or hornfels

Quartz (SiO₂) in a fine-grained silicate matrix; exact rock identification requires testing

Dark gray foliated metamorphic rock, likely slate or phyllite

Slate/phyllite; commonly quartz, muscovite/illite, chlorite, and graphite or carbonaceous matter

Foliated Gneiss

Gneiss (Metamorphic Rock)

Graphite-rich metamorphic rock (graphitic schist)

Graphitic schist; chiefly graphite (C), quartz (SiO₂), and mica minerals

Likely foliated metamorphic rock (gneiss or schist)

Quartz–feldspar–mica metamorphic rock; exact identification requires a fresh surface or tests

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with feldspar, mica, or iron oxides

White quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, possibly micaceous or feldspathic

Banded Gneiss

Gneiss (Metamorphic Rock)

Quartz with Schist Inclusion

Crystalline Silicon Dioxide (SiO2) with Muscovite/Biotite Schist

Sandstone or Quartzite

Arenite (if sedimentary) / Quartzite (if metamorphic)

Weathered quartz-rich metamorphic rock, possibly quartzite or gneiss

Quartz-dominant silicate rock; likely quartz (SiO₂) with feldspar, mica, and minor iron-oxide staining

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with feldspar and mica impurities

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly quartz (SiO₂), with minor feldspar, mica, and iron-oxide staining

Quartz-rich metamorphic rock (probable quartzite)

Quartzite; predominantly crystalline SiO₂, with possible mica and iron-oxide impurities

Weathered quartz-rich metamorphic rock

Likely quartzite or quartz-veined schist; primarily SiO₂ with possible mica, feldspar, and iron oxides

Weathered quartz-rich metamorphic rock (probable quartzite)

Quartzite, predominantly crystalline SiO₂, possibly derived from sandstone

Weathered quartz-rich metamorphic rock (probable quartzite)

Quartzite; predominantly microcrystalline quartz (SiO₂), with possible mica, feldspar, and iron-oxide impurities

Gray metamorphic rock, likely slate or phyllite

Fine-grained foliated rock, probably quartz–mica slate/phyllite

Milky Quartz with Chlorite Schist Inclusions

Quartz (SiO2) with Chlorite Group silicates (typically (Mg,Fe)3(Si,Al)4O10(OH)2)

Weathered garnet-bearing gneiss

Quartz–feldspar–mica gneiss with almandine garnet, chiefly Fe₃Al₂(SiO₄)₃

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica or feldspar

Mica-rich metamorphic rock, likely phyllite or mica schist

Quartz–muscovite phyllite/schist; commonly dominated by muscovite mica, quartz, and minor feldspar