Metamorphic Mineral

Emerald

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Fuchsite Gneiss or Schist

Muscovite (variety Fuchsite) within Metamorphic Host Rock

Quartz-Veined Slate or Greenstone

Metamorphic rock with quartz vein (SiO2)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Epidote

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

Likely greenstone (chlorite/epidote-altered basalt), waterworn pebble

Greenschist-facies metabasalt; commonly composed of chlorite, actinolite, epidote, and albite

Greenstone (likely metamorphosed basalt)

Metabasalt/greenstone; commonly composed of chlorite, actinolite, epidote, albite, and quartz

Tumbled green aventurine

Quartz (SiO₂) with fuchsite or other green mica inclusions

Tumbled green aventurine (probable)

Quartzite composed chiefly of quartz (SiO₂), with green fuchsite or other mica inclusions

Magnetite-rich ironstone (probable magnetite ore)

Magnetite, Fe₃O₄, likely in a fine-grained ironstone matrix

Pyrite

Iron Pyrite (FeS2)

Pyrite (on the right) and Magnetite or Hematite (on the left)

Iron Sulfide (FeS2) and Iron Oxide (Fe3O4 or Fe2O3)

Rhodonite

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

Yellow Calcite

Calcium Carbonate (CaCO3)

Calcite

Calcium Carbonate (CaCO3)

Pyrite

Iron Disulfide (FeS2)

Optical Calcite

Calcium Carbonate (CaCO3)

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Quartz

Silicon Dioxide (SiO2)

Yellow Calcite

Calcium Carbonate (CaCO3)

Quartz with Mica/Host Rock

Silicon Dioxide (SiO2) with Phyllosilicates

Gneiss (Metamorphosed Granitic Rock)

Gneiss (composed mainly of quartz, feldspar, biotite, and/or hornblende)

Epidote and Quartz in Basalt

Epidote [Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)] in Metabasalt

Clear Quartz (Faceted)

Silicon dioxide (SiO2)

Unidentified gray-green rock specimen

Possibly banded gneiss or another foliated metamorphic rock; identification is uncertain from the image

Quartz Mineral

Silicon Dioxide (SiO2)

Foliated Gneiss

Gneiss (Metamorphic Rock)

Mica-rich schist (likely biotite schist)

Mica schist, composed chiefly of quartz and mica; exact minerals cannot be confirmed from the image

Polished greenstone pebble

Likely serpentinite (serpentine-group minerals); identification from appearance alone is uncertain

Gneiss

Gneiss (Metamorphic Rock)

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Black tourmaline (likely schorl)

Schorl, NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Tumbled quartz-rich pebble

Quartz (SiO₂), likely with iron-oxide staining and minor inclusions

Milky quartz fragment

Quartz (silicon dioxide, SiO₂)

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions) - SiO2

Quartz-rich rock, likely granite or quartz-bearing metamorphic rock

Undetermined; possibly granitic rock composed mainly of quartz and feldspar, with mica or other dark minerals

Gneiss

Gneiss (Metamorphic Rock)

Prehnite

Ca2Al(AlSi3O10)(OH)2

Quartz fragment

Silicon Dioxide (SiO2)

Pale green stone, possibly serpentine

Serpentinite (dominantly serpentine-group minerals; visual identification is uncertain)

Blue Quartz

Silicon Dioxide (SiO2) with inclusions