Metamorphic (Low Grade)

Jadeite

Jadeite (NaAlSi2O6)

Weathered greenstone / altered rock fragment

Probable chlorite–epidote–actinolite-rich metavolcanic rock; exact identification requires testing

Greenstone (or Greywacke/Metasediment Pebble)

Metamorphosed Mafic Rock / Chlorite Schist

Greenstone (Epidosite or Serpentinite)

Metabasalt / Epidote-Chlorite Schist

Epidote

Epidote Group (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Emerald

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Foliated metamorphic rock (likely phyllite or fine-grained schist)

Phyllite–schist, chiefly quartz, mica, and clay-derived silicates

Anthracite Coal

Anthracite (Carbon-rich metamorphic rock)

Likely slate or fine-grained schist

Metamorphosed mudstone; commonly quartz–mica–chlorite, with slate dominated by aligned clay minerals

Weathered quartz-rich pebble, possibly metasandstone

Quartz-rich metasandstone (provisional); mainly SiO₂ with minor feldspar, mica, or iron oxides

Likely chlorite schist or altered mafic rock

Chlorite–actinolite schist; commonly composed of chlorite, actinolite/amphibole, epidote, and albite

Polished greenstone pebble (likely epidote-bearing stone)

Epidote–chlorite amphibolite or altered basalt; composition likely epidote, chlorite, amphibole/pyroxene, and iron oxides

River Cobble (likely Metasedimentary)

Metasedimentary Rock / Quartz-rich Sandstone

Waterworn greenstone pebble

Likely serpentinite or chlorite-rich metamorphic rock; exact identification requires testing

Greenstone / Greenschist

Greenschist (composed primarily of Chlorite, Epidote, and Actinolite)

Banded Iron Formation (BIF) / Tiger Iron

Ferruginous Chert (primarily Quartz [SiO2] and Hematite/Magnetite [Fe2O3/Fe3O4])

Greenstone

Greenschist (metamorphosed mafic igneous rock)

Anthracite Coal

Anthracite (Carbon)

Jade

Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (NaAlSi2O6)

Gray slate (probable)

Slate; chiefly fine-grained mica/clay minerals, quartz, and chlorite

Quartz-rich translucent fragment

Quartz, silicon dioxide (SiO₂), possibly chalcedony or vein quartz

Likely quartz-rich stone, possibly quartzite or milky quartz

Quartz (silicon dioxide, SiO₂); exact rock identification is uncertain from the image

Green Schist

Greenschist (composed of Chlorite, Actinolite, and Epidote)

Dark green mineral specimen, possibly serpentine or epidote

Tentatively serpentine-group mineral, Mg₃Si₂O₅(OH)₄, or epidote, Ca₂(Al,Fe)₃Si₃O₁₂(OH)

Tumbled green aventurine/quartzite chips (probable)

Quartz, SiO₂, commonly with fuchsite or chlorite inclusions

Polished greenstone (likely serpentine or altered basalt)

Serpentinite, mainly serpentine-group minerals (Mg₃Si₂O₅(OH)₄); exact identification requires testing

Kyanite (in Schist Matrix)

Kyanite (Al2SiO5)

Greenstone (likely altered basalt)

Metabasalt/greenschist; chiefly chlorite, actinolite, epidote, albite, and quartz

Gray metamorphic rock, likely slate or phyllite

Probably quartz–mica phyllite or fine-grained slate; exact identification requires testing

Chlorite-rich schist (probable greenschist)

Chlorite–quartz–mica schist; commonly derived from basalt or shale under greenschist-facies metamorphism

Unidentified River Rock or Mudstone

N/A (Generic rock fragment)

Quartzite pebble

Crystalline silica (SiO2)

Milky quartz-bearing rock, possibly quartzite

Quartz (SiO₂), likely in a quartzite or quartz-rich metamorphic matrix

Schist (Garnet-Mica Schist)

Garnet-Mica Schist

Eclogite

Eclogite (Omphacite + Almandine-Pyrope Garnet)

Nephrite Jade

Nephrite (a variety of the Calcium magnesium iron silicate mineral series Actinolite), Ca2(Mg, Fe)5Si8O22(OH)2

Jadeite Jade

NaAlSi2O6 (Sodium Aluminum Silicate)

Anthracite Coal

Anthracite (Carbon-rich metamorphic coal)

Greenstone / Basalt

Metabasalt (often containing Chlorite, Epidote, and Actinolite)

Tumbled dark stones, likely basalt and slate

Basalt (fine-grained mafic rock) and slate (foliated metamorphic rock); exact identification is uncertain from the image

Polished red tiger’s-eye (likely)

Quartz pseudomorph after crocidolite; chiefly SiO₂ with iron oxides

Tiger’s eye

Quartz (SiO₂) with fibrous crocidolite pseudomorphs and iron oxides