Sedimentary Rock (Metamorphosed)

Weathered quartz-rich rock, likely quartzite

Quartzite (mostly microcrystalline quartz, SiO₂), possibly iron-oxide-stained sandstone

Likely weathered granite or granitic gneiss

Granite/granitic gneiss, composed mainly of quartz, feldspar, and mica; exact identification is uncertain from the photograph

Micaceous schist (likely biotite schist)

Biotite–quartz–feldspar schist; commonly containing muscovite and/or garnet

Tumbled dark olive stone, likely serpentinite or greenstone

Probable serpentinite, dominated by antigorite/lizardite minerals; exact identification requires testing

Tumbled greenstone pebble

Greenstone (metamorphosed mafic volcanic rock; commonly chlorite, actinolite, epidote, and albite)

Quartzite Pebble

Quartzite (Metamorphosed Quartz Sandstone, SiO2)

Quartz-rich granite or granitic gneiss

Granite; chiefly quartz (SiO₂), feldspar, and mica

Water-worn green pebble

Likely altered basalt or greenstone; precise identification requires testing

Weathered quartz-rich rock, possibly milky quartz/quartzite

Quartz (SiO₂), likely in a quartzite or silicified host rock

Serpentinized ultramafic rock (serpentinite)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, olivine, pyroxene, and brucite

Yellow-brown quartz-rich pebble (possibly iron-stained chert or quartzite)

Quartz (SiO₂), likely with iron-oxide staining; exact identification requires hardness and acid tests

Quartzite with Quartz Vein

Metamorphosed Quartz-rich Arenite (SiO2)

Quartzite

Quartzite, composed predominantly of recrystallized quartz (SiO₂)

Likely pyrite-bearing metamorphic rock

Quartz–mica schist or phyllite with disseminated pyrite (FeS₂)

Gray metamorphic rock, likely slate or phyllite

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

Serpentinized ultramafic rock (likely serpentinite)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, olivine, pyroxene, and sulfides

Slate

Metamorphosed Shale (Fine-grained Foliated Metamorphic Rock)

Small rounded orange-brown stone, likely iron-stained quartzite or sandstone

Indeterminate; probable quartz-rich sandstone/quartzite with iron-oxide staining

Quartz-rich metamorphic rock (likely quartzite)

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

Milky quartz-rich rock

Quartz (SiO₂), likely massive quartz in a quartz vein or quartzite

Rounded quartz-rich pebble

Likely chert or quartzite; predominantly microcrystalline quartz (SiO₂)

Quartzite with Epidote

Meta-quartzite containing Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH))

Greenstone / altered mafic rock

Likely chlorite–actinolite schist or metabasalt; exact identification requires testing

Slate

Slate (Metamorphic Rock)

Serpentinized ultramafic rock with chromite

Serpentinite; chiefly serpentine-group minerals, Mg-rich silicates, with probable chromite and minor magnetite

Weathered iron-stained quartz-rich rock, possibly rhyolite or quartzite

Indeterminate silica-rich rock; likely quartz (SiO₂) with iron oxides and clay alteration

Iron-rich quartzite or limonite-bearing rock

Quartzite (SiO₂) with iron oxides/hydroxides, chiefly hematite and goethite

Iron-rich metamorphic rock (probable garnet-bearing schist or quartzite)

Garnet–quartz–mica schist/quartzite; composition likely quartz (SiO₂), iron oxides/hydroxides, mica, and possible almandine garnet

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if the grainy texture is rock-wide

Garnet amphibolite / Metamorphic Rock

Garnet Amphibolite (Hornblende - Almandine schist/gneiss)

Weathered granite or granitic gneiss

Felsic plutonic rock, primarily quartz, feldspar, and mica; possible gneissic deformation

Polished gray pebble, likely quartzite or fine-grained granite

Probable quartzite (mostly microcrystalline SiO₂); identification is uncertain from the photograph

Tumbled speckled pebble, likely marble or limestone

Calcite-rich carbonate rock; possibly impure marble (CaCO₃)

Iron-stained quartz-rich rock (likely limonite-bearing quartzite)

Quartzite, predominantly quartz (SiO₂), with iron oxides/hydroxides such as limonite/goethite

Greenstone / altered mafic rock

Likely chlorite–epidote–actinolite schist or altered basalt (greenstone); exact identification requires thin-section or chemical testing.

Weathered mica-rich rock fragment

Likely biotite granite or granitic gneiss; exact identification is uncertain from the photograph

Quartzite with Schist Inclusions

Metamorphosed Quartzite (SiO2) with minor mica/chlorite schist

Quartzite Pebble (with possible inclusion)

Metamorphosed Quartz Sandstone (SiO2 with impurities)

Shale (possibly)

Shale (fine-grained clastic sedimentary rock)

Likely galena-bearing metamorphic sulfide ore

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

Weathered gray rock fragment

Likely quartz-rich sandstone or weakly metamorphosed sandstone; exact identification is uncertain from the photograph

Rounded greenish stone, likely basalt or metamorphic greenstone

Probable fine-grained mafic rock; possible basalt (plagioclase–pyroxene) or greenschist-facies greenstone