Metamorphic Or Sedimentary Depending On Local Grade

Biotite schist

Mica schist; chiefly quartz, feldspar, and biotite mica

Banded gneiss (likely orthogneiss or paragneiss)

Gneiss; composition commonly quartz + feldspar + mica, with possible amphibole/biotite

Jasper

Agate/Jasper (Microcrystalline Quartz, SiO2)

Jasper

Jasper (Silica/Quartz) - SiO2

Schist

Metamorphic Rock (Schist)

Slate

Slate; fine-grained metamorphosed shale, commonly quartz–muscovite/chlorite rich

Blue Kyanite

Kyanite (Al2SiO5)

Diorite

Phaneritic Intermediate Igneous Rock

Weathered quartz-rich rock, possibly quartzite

Quartzite (mostly SiO₂), tentatively identified

Green Fluorite

Calcium Fluoride (CaF2)

Biotite-rich schist (likely mica schist)

Mica schist; predominantly quartz, biotite mica, and feldspar

Sandstone (Weathered Cobble)

Clastic Sedimentary Rock (primarily SiO2)

Sandstone with Quartz Vein

Arenite with Quartz (SiO2) protrusion

Layered sandstone (likely building stone)

Quartz-rich sandstone; exact variety cannot be determined from the image

Milky Quartz with Iron Staining

Crystalline Silicon Dioxide (SiO2)

Granite Boulder (Glacial Erratic)

Granite

Sandstone (Quartzose)

Arenite (primarily SiO2)

Gneiss (possibly migmatitic or strongly folded banded gneiss)

Banded quartz–feldspar–mica gneiss; variable composition, commonly quartz + plagioclase/alkali feldspar + biotite/muscovite ± amphibole

Seraphinite (Clinochlore)

Clinochlore (Mg,Fe2+)5Al(Si3Al)O10(OH)8

Garnet Gneiss

Gneiss containing almandine-pyrope garnet

Gravelly, weathered sediment (likely glacial till)

Unconsolidated diamicton; mixed lithologies, commonly including quartz, feldspar, and weathered silicate rock fragments

Likely blue-gray slate

Slate, a fine-grained metamorphic rock composed mainly of mica-group minerals and quartz

Milky Quartz with Mica inclusions

Silicon Dioxide (SiO2) with Muscovite/Biotite

Weathered Gabbro or Diorite (Igneous Cobble)

Phaneritic Basic/Intermediate Igneous Rock

Slate

Metamorphic Pelitic Rock

Banded Calcite (often sold as Onyx)

Calcite (Calcium Carbonate, CaCO3)

Sandstone (Ferruginous)

Arenite with Iron-Oxide Cement

Gray slate or fine-grained metamorphic rock

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

Slate fragment

Slate; predominantly fine-grained mica/clay minerals, commonly muscovite, chlorite, and quartz

Garnet-bearing metamorphic rock

Likely garnet schist or garnet-bearing mica schist; garnet is commonly almandine, Fe₃Al₂(SiO₄)₃

Granite Gneiss

Granitic Gneiss

Weathered schist

Mica schist, typically quartz–mica schist

Garnet-Bearing Gneiss

Garnetiferous Feldspathic Gneiss

Greenstone / Glauconitic Siltstone

Metabasalt or Glauconite-rich Sedimentary Rock

Weathered gray sandstone or siltstone

Clastic siliciclastic rock, primarily quartz and feldspar grains cemented by silica or carbonate

Greenschist

Greenschist facies metamorphic rock

Weathered metamorphic rock, likely schist or phyllite

Quartz–mica schist/phyllite (exact identification requires a fresh surface and tests)

Pyrite

Iron Sulfide (FeS2)

Banded gneiss

Gneiss, commonly quartz–feldspar–mica gneiss

Chert (possibly a worked stone flake)

Microcrystalline quartz, SiO₂

Veined Quartzite / Vein-filled Sedimentary Rock

Siliciclastic rock with iron oxide-filled fractures

Green Schist

Greenschist (Chlorite Schist)