Metamorphic Rock

Pyrite-bearing metamorphic rock (likely schist or quartzite)

Mica/quartz-rich metamorphic matrix with pyrite (FeS₂), possibly chalcopyrite (CuFeS₂)

Quartz-rich metamorphic rock, likely quartzite

Quartzite (mostly microcrystalline quartz, SiO₂), possibly mica-bearing

Likely galena-bearing metamorphic sulfide ore

Galena (PbS), possibly with pyrite and/or sphalerite in a schistose host

Weathered quartz-rich metamorphic rock (probable quartzite)

Quartzite, predominantly crystalline SiO₂, possibly derived from sandstone

Weathered quartz-rich metamorphic rock, possibly quartzite

Quartzite (SiO₂-rich metamorphic rock), with probable feldspar, mica, and iron-oxide staining

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, with possible iron-oxide and dark mica/mineral inclusions

Mica-rich metamorphic rock, likely schist

Muscovite- or biotite-bearing schist; composition commonly quartz + mica ± feldspar

Weathered quartz-rich metamorphic rock, possibly quartzite

Quartzite (predominantly SiO₂), with iron-oxide staining and minor accessory minerals

Dark gray metamorphic rock fragment, likely slate or schist

Fine-grained foliated silicate rock; composition likely quartz, feldspar, mica, and/or chlorite

Banded gneiss or banded metamorphic rock

Gneiss, likely quartz–feldspar–biotite gneiss

White quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, possibly micaceous or feldspathic

Quartz-rich metamorphic rock, likely mica schist

Mica schist; chiefly quartz (SiO₂) and mica, likely muscovite/biotite, with possible feldspar

Coarse-grained gray metamorphic rock, likely gneiss or granitic gneiss

Quartz–feldspar–mica gneiss; exact identification requires petrographic or chemical testing

Biotite-bearing metamorphic rock, likely schist

Mica schist; quartz–feldspar–biotite assemblage

Weathered quartz-rich metamorphic rock, likely quartzite

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

Quartz-rich metamorphic rock, likely quartzite

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

Foliated metamorphic rock, likely slate or phyllite

Fine-grained metapelite; commonly quartz–mica–chlorite with possible graphite

Quartz-rich metamorphic rock, likely quartzite

Quartzite, composed predominantly of quartz (SiO₂), with dark biotite, amphibole, or iron-oxide inclusions

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly quartz (SiO₂), with minor iron-oxide staining and possible mica/clay minerals

Weathered mica-rich metamorphic rock (probable schist)

Mica schist, likely muscovite–biotite schist with quartz and feldspar

Weathered gray metamorphic rock, likely phyllite or slate

Micaceous quartz–phyllosilicate rock; commonly quartz + muscovite/illite ± chlorite

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite (mostly SiO₂), possibly micaceous quartzite or quartz-rich schist

Garnet-bearing metamorphic rock, likely mica schist

Biotite–garnet schist; commonly includes quartz, feldspar, biotite, and almandine garnet

Mica-rich metamorphic rock, likely schist

Biotite–muscovite schist, possibly garnet-bearing

Quartz-bearing metamorphic rock, likely garnet-mica schist

Quartz–mica schist with probable garnet and iron-oxide minerals

Quartz-veined metamorphic rock, likely greenschist or altered basalt

Chlorite–actinolite schist or metabasalt with a milky quartz vein

Dark green metamorphic rock, likely serpentinite

Serpentinite, composed mainly of serpentine-group minerals (antigorite, lizardite, or chrysotile), commonly with magnetite and minor chlorite/talc

Quartz–mica metamorphic rock, likely schist

Quartz–muscovite/biotite schist; predominantly SiO₂ quartz with phyllosilicate micas

Weathered quartz-rich metamorphic rock (probable quartzite)

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

Weathered quartz-rich metamorphic rock, likely quartzite

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

Gneiss (Metamorphic Rock)

Gneiss (variable mineral formula primarily containing Quartz, Feldspar, and Mica)

Quartz-veined metamorphic rock, likely greenschist or altered metavolcanic

Chlorite–actinolite–epidote-bearing metavolcanic rock with quartz veins; exact identification requires testing

Quartz-Veined Gneiss or Metamorphic Rock with Quartz Veins

Quartz-veined metamorphic rock (Silicate mineral assemblage)

Rounded gray metamorphic rock, likely quartzite or gneiss

Quartz-rich metamorphic rock; exact identification is uncertain from the photograph

Gneiss (Metamorphic Rock)

Gneiss

Gneiss (Metamorphic Rock)

Gneiss (high-grade regional metamorphic rock)

Gneiss (Metamorphic Rock)

Gneiss

Veined quartz-bearing metamorphic rock

Likely quartzite or siliceous schist with iron-oxide staining

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, possibly with mica or iron-oxide impurities

Quartz-rich metamorphic rock, likely quartzite

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

Dark, mica-rich metamorphic rock (probable schist or gneiss fragment)

Likely biotite–quartz–feldspar schist; exact identification requires testing

Dark gray metamorphic rock, likely hornfels or fine-grained amphibolite

Hornfels/amphibolite; commonly quartz, feldspar, amphibole, biotite, and minor sulfides