Metamorphic

Rhodonite

Rhodonite (Manganese Silicate), (Mn,Fe,Mg,Ca)SiO3

Quartzite with Mafic Intrusion (Gneiss/Schist Contact)

Metamorphic Quartzite (SiO2) with Amphibole/Biotite Schist

Basalt Pebble

Extrusive Igneous Rock

Slate

Foliated low-grade metamorphic rock

River Pebble (Gneiss or Quartzite mixture)

Metamorphic rock (Commonly Gneissic)

Blue Sapphire

Corundum (Al2O3)

Citrine

Silicon Dioxide (SiO2)

Garnet

Almandine Garnet (Fe3Al2(SiO4)3)

Quartzite

Quartzite

Quartzite

Quartzite

Fuchsite

Cr-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(F,OH)2)

Quartz with Muscovite Mica

Silicon Dioxide (SiO2) with Potassium Aluminum Silicate Hydroxide Fluoride (KAl2(AlSi3O10)(F,OH)2)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Fuchsite

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Garnet-bearing metamorphic rock, likely mica schist

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

Small rounded, foliated metamorphic pebble (likely greenschist)

Greenschist, commonly composed of chlorite, actinolite, and albite; exact identification requires testing

Biotite Schist

Biotite Schist (predominantly K(Mg,Fe)3AlSi3O10(OH,F)2)

Garnet-bearing schist (likely)

Garnet mica schist, with almandine garnet (Fe₃Al₂(SiO₄)₃) likely

Likely biotite-rich schist

Mica schist, composed chiefly of biotite and quartz; exact identification is uncertain from the image.

Likely gneiss pebble

Foliated quartz–feldspar gneiss, with dark biotite or amphibole

Amphibolite

Amphibolite, composed mainly of amphibole and plagioclase feldspar

Tumbled limestone or marble

Calcite-rich carbonate rock; likely limestone (CaCO₃), possibly marble

Mica-rich schist (probable)

Mica schist, composed mainly of mica minerals with quartz and possibly feldspar

Weathered garnet-bearing rock (possibly garnet schist)

Garnet-bearing mica schist; likely almandine garnet (Fe₃Al₂(SiO₄)₃) with mica and quartz

Small banded metamorphic rock fragment

Indeterminate foliated metamorphic rock; possibly mica schist or gneiss

Likely mica-rich schist (possibly phyllite)

Muscovite–biotite schist; exact identification requires examination of a fresh surface

Gneiss

Foliated quartz–feldspar gneiss, likely biotite-bearing

Banded amphibolite (hornblende schist)

Amphibolite, chiefly hornblende + plagioclase feldspar, commonly with biotite and quartz

Foliated mica-rich metamorphic rock, likely schist

Muscovite–biotite schist, possibly garnet-bearing

Gneiss with Quartz Vein

Metamorphic Gneiss with Quartz (SiO2) and Feldspar Injection

Sapphirine in Matrix

Sapphirine (Mg,Al)8(Al,Si)6O20

Garnet (Almandine-Pyrope)

Almandine-Pyrope Mg3Al2(SiO4)3 to Fe3Al2(SiO4)3

Green Slate or Metamorphic Rock with Moss/Lichen

Metamorphic rock / Phyllite or Slate variant

Fuchsite

Chromian Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Quartz

Silicon Dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide, FeS2

Pyrite in Matrix

Iron Sulfide (FeS2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)