Metamorphic (Low Grade)

Greenstone / Glauconitic Siltstone

Metabasalt or Glauconite-rich Sedimentary Rock

Anthracite Coal

Anthracite (Carbon-based sedimentary-derived metamorphic rock)

Amazonite

Microcline Feldspar (KAlSi3O8)

Tiger's Eye

Quartz pseudomorph after Crocidolite (SiO2 with Fe oxide inclusions)

Banded Jasper (Chert)

Silicon Dioxide (SiO2)

Epidote

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

Ferruginous Sandstone

Clastic Sedimentary Rock (Iron-rich)

Milky quartz (likely quartz fragment)

Quartz, silicon dioxide (SiO₂)

Greenstone (Rough Jadeite or Nephrite)

Sodium aluminum silicate (Jadeite) / Calcium magnesium iron silicate (Nephrite)

Likely weathered greenstone

Metabasalt (greenstone), composed chiefly of chlorite, actinolite, epidote, and albite

Biotite-rich gneiss

Foliated quartz–feldspar–mica gneiss; mainly quartz, plagioclase/alkali feldspar, and biotite

White quartz-rich rock, possibly milky quartz

Quartz (SiO₂), possibly quartzite or calcite-bearing material

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Emerald in Matrix

Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities

Polished tiger’s-eye

Chatoyant quartz (microcrystalline quartz, SiO₂, with fibrous riebeckite/crocidolite pseudomorphs)

Banded gneiss (polished/tumbled cobble)

Gneiss, composed chiefly of quartz, feldspar, and mica/amphibole

Greenschist

Greenschist (chlorite-epidote schist)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Jadeite

NaAlSi2O6; Jadeite silicate mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Weathered metamorphic rock, likely chlorite schist or greenstone

Chlorite-rich schist/greenschist; exact identification requires testing

Rough Ruby (Corundum) in Zoisite Matrix

Al2O3 (Aluminum Oxide) with Ca2Al3(SiO4)3(OH)

Nephrite Jade

Ca2(Mg,Fe)5Si8O22(OH)2 (Actinolite-Tremolite series)

Weathered basalt or mafic metavolcanic rock

Basalt, possibly altered to greenstone (chlorite–epidote–actinolite assemblage)

Serpentinite (often containing Jadeite/Nephrite)

Antigorite-rich Serpentine Rock, (Mg, Fe)3Si2O5(OH)4

Greenschist (likely chlorite schist)

Greenschist-facies metamorphic rock; commonly quartz + chlorite ± actinolite, epidote, albite, and mica

Greenstone (likely altered basalt or serpentinite)

Chlorite–epidote amphibolite/greenschist or serpentinite; exact identification requires testing

Greenstone / altered basalt (probable)

Chlorite–epidote–actinolite aggregate; commonly metabasalt (greenstone)

Tumbled gray stone, likely slate or fine-grained metamorphic rock

Probable slate/phyllite; composition mainly quartz, mica, and feldspar

Epidote-rich rock (likely epidotite or altered basalt)

Epidote, Ca₂(Al,Fe³⁺)₃(SiO₄)₃(OH); possibly epidote-bearing mafic rock

Likely chlorite-bearing schist (possibly greenschist)

Chlorite–quartz–mica schist; commonly contains muscovite/biotite and feldspar

Tiger’s-eye (likely red/brown variety)

Chatoyant quartz, chiefly SiO₂, pseudomorphous after crocidolite (riebeckite)

Blue-gray metamorphic rock, likely slate or phyllite

Slate/phyllite; chiefly quartz, muscovite/illite, chlorite, and minor feldspar

Anthracite Coal

Anthracite (Carbon)

Quartz with Chlorite / Greenschist

Quartz vein in Greenschist (SiO2 with Chlorite group minerals)

Banded Slate or Siltstone with Quartz/Calcite Veins

Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)

Citrine (Yellow Quartz)

Silicon Dioxide (SiO2)

Likely milky quartz

Quartz (silicon dioxide, SiO₂), possibly quartz-rich rock or calcite

Milky quartz (rough quartz fragment)

Quartz, silicon dioxide (SiO₂)

Milky Quartz with Chlorite/Moss Infusions

Silicon Dioxide (SiO2)

Serpentinite

Serpentinite (complex of Antigorite, Lizardite, and Chrysotile, Mg3Si2O5(OH)4)

Tumbled tiger’s-eye

Quartz variety, SiO₂, with crocidolite-derived fibrous inclusions