Metamorphic Rock

Foliated metamorphic rock, likely slate or phyllite

Slate–phyllite; primarily quartz, mica, and clay-derived minerals

Iron-rich metamorphic rock, likely hematite-bearing schist or ironstone

Hematite/goethite-rich quartz–mica schist or banded ironstone; Fe₂O₃ and FeO(OH) are probable major iron minerals

Raw graphite-rich metamorphic rock (probable graphite schist)

Graphite schist; predominantly crystalline carbon (graphite, C) with mica and quartz

Vein-bearing metamorphic rock, likely gneiss or schist

Quartz-feldspar–mica metamorphic rock; exact identification requires testing

Iron-rich metamorphic rock, likely banded iron formation fragment

Hematite–magnetite-rich quartzite (BIF); Fe₂O₃/Fe₃O₄ with SiO₂

Dark gray foliated metamorphic rock, likely slate or phyllite

Slate/phyllite; chiefly quartz, mica, and chlorite

Dark foliated metamorphic rock, probably schist

Mica schist, likely quartz–muscovite/biotite schist

Quartz-rich metamorphic rock (likely quartzite)

Quartzite, dominantly crystalline SiO₂, with probable iron-oxide staining and minor feldspar/mica

Quartz-rich metamorphic rock, likely quartzite

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

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, possibly with iron-oxide staining and minor feldspar or mica

Likely quartz-rich metamorphic rock (quartzite or milky quartz)

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

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline to granular SiO₂, possibly with mica and feldspar

Weathered quartz-rich metamorphic rock, possibly quartzite

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

Quartz-rich metamorphic rock, likely quartzite

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

Likely quartz-rich metamorphic rock (quartzite or quartz-veined schist)

Quartzite/siliceous schist; chiefly quartz (SiO₂), with probable mica and iron-oxide staining

Dark metamorphic rock, possibly schist

Mica schist (probable; commonly quartz + muscovite/biotite, with possible graphite or chlorite)

Tumbled gray-green metamorphic rock, likely serpentinite or chlorite schist

Serpentinite/chlorite-rich ultramafic metamorphic rock; commonly dominated by antigorite, lizardite, or chlorite with minor magnetite and talc

Quartz-rich metamorphic rock, likely milky quartz or quartzite

Quartz (SiO₂); possibly quartzite composed predominantly of recrystallized quartz

Likely basalt or mafic metamorphic rock

Fine-grained basalt, possibly altered; chiefly plagioclase feldspar and pyroxene, with minor iron-titanium oxides

Quartz-bearing granite or pegmatite fragment

Likely granitic material composed mainly of quartz (SiO₂), feldspar, and possibly biotite or hornblende

Fossilized bivalve shell or shell-rich limestone

Likely an indeterminate fossil mollusk; calcite/aragonite (CaCO₃), possibly preserved in limestone

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Greenschist (or Serpentinite with Manganese Dendrites)

Greenschist facies metamorphic rock

Dark mica-rich metamorphic rock, likely schist

Mica schist, probably biotite–muscovite schist; exact identification requires testing

Gneiss

Gneiss (Foliated Metamorphic Rock)

Dark mica-rich metamorphic rock, likely schist

Mica schist; commonly quartz–biotite ± muscovite schist

Gneiss

Gneiss (Foliated Metamorphic Rock)

Slate

Slate (foliated metamorphic rock)

Schist

Mica Schist (Metamorphic Rock)

Phyllite

Phyllite (regional metamorphic rock)

Schist

Mica Schist (Metamorphic Rock)

Gneiss

Gneiss (Foliated Metamorphic Rock)

Gneiss (specifically a weathered or stream-worn specimen)

Gneiss (Foliated Metamorphic Rock)

Banded Gneiss

Gneiss (Foliated Metamorphic Rock)

Gneiss

Gneiss (foliated metamorphic rock)

Slate

Foliated Metamorphic Rock (Slate)

Granitic Gneiss Pebble

Gneiss (felsic metamorphic rock)

Gneiss

Gneiss (Foliated Metamorphic Rock)

River Rock (Gneiss/Schist mix)

Foliated Metamorphic Rock (Gneiss)

Schist

Crystalline Metamorphic Rock (Schistose)

Phyllite

Phyllite (Foliated metamorphic rock)

Schist

Mica Schist (Metamorphic Rock)