Metamorphic (Low Grade)

Graphitic schist (probable)

Graphite-bearing mica schist; chiefly quartz, mica, and graphite

Polished tiger’s-eye

Quartz-rich tiger’s-eye; mainly SiO₂ with iron oxides and fibrous pseudomorphs after crocidolite

Epidote

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

Pyrite (Limonite Pseudo-morph after Pyrite)

Iron sulfide (FeS2) transitioning to Iron oxide-hydroxide (FeO(OH)·nH2O)

Dark gray metamorphic rock, likely slate or phyllite

Slate/phyllite; commonly quartz–mica–chlorite aggregate

Bornite (Peacock Ore)

Bornite (Cu5FeS4)

Tumbled green serpentine (likely nephrite jade imitation/alternative)

Serpentine-group minerals, chiefly antigorite and lizardite; composition approximately Mg₃Si₂O₅(OH)₄

Greenschist / Migmatite

Regional Metamorphic Complex (Facies: Greenschist to Amphibolite)

Ruby (Corundum)

Aluminum oxide (Al2O3) with Chromium traces

Tumbled tiger’s-eye

Tiger’s-eye (chatoyant quartz), SiO₂, pseudomorphic fibrous quartz after crocidolite

Rounded greenstone cobble

Likely greenschist or altered basalt; composition commonly chlorite, epidote, actinolite, albite, and quartz

Serpentinite

Serpentinite (Hydrated Magnesium Silicate Mg3Si2O5(OH)4)

Iron-rich jasper (likely brecciated jasper)

Microcrystalline quartz/chalcedony (SiO₂) colored by hematite/goethite; possibly iron formation

Prehnite

Prehnite (Ca2Al2Si3O10(OH)2)

Slate or thinly bedded shale

Slate; primarily fine-grained mica/clay minerals and quartz

Epidote in Quartz

Epidote (Ca2(Al,Fe)3(SiO4)3(OH)) in Milky Quartz (SiO2)

Jadeite (Nephrite-Jadeite blend)

Jadeite (NaAlSi2O6)

Lapis Lazuli

Lapis Lazuli (Complex silicate: Na8[Al6Si6O24]Sn)

Likely tumbled tiger’s eye

Quartz (SiO₂) with fibrous crocidolite pseudomorphed by quartz; iron oxides produce the golden-brown color

Yellow Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Green Schist

Greenschist (composed of chlorite, epidote, and actinolite)

Purple Slate

Foliated slate (Pelitic origin)

Greenstone

Metamorphic mafic rock (greenschist facies)

Emerald in Quartz Matrix

Beryl (Be3Al2Si6O18) with trace Chromium/Vanadium

Ruby

Corundum (Al2O3 with Chromium traces)

Greenstone (Epidote/Chlorite-rich Metabasalt)

Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))

Greenstone

Metamorphic mafic rock (greenschist facies)

Greenstone / Graywacke

Metagraywacke (Chlorite-grade schistose rock)

Dark slate or fine-grained metamorphic rock

Slate; chiefly fine-grained phyllosilicates, quartz, and feldspar

Slate

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

Schist

Mica Schist

Raw Emerald in Matrix

Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities

Gossan (Iron Hat)

Goethite-Hematite rich weathered rock (Fe-hydroxides)

Gray slate

Slate; fine-grained foliated metamorphic rock composed mainly of mica and quartz

Likely foliated metamorphic rock (slate or phyllite)

Fine-grained, foliated rock; exact identification is uncertain from the photograph

Rounded greenstone pebble

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

Greenschist

Greenschist (Chlorite-Epidote-Actinolite Schist)

Anthracite Coal

Anthracite (high-rank coal)

Greenstone pebble (likely altered basalt)

Chlorite–actinolite–epidote altered basalt; precise identification requires testing

Greenstone, possibly serpentine or altered basalt

Serpentinite (Mg₃Si₂O₅(OH)₄) or chlorite-epidote altered basalt; identification is uncertain from the image

Weathered greenstone

Metamorphosed mafic rock, commonly chlorite–actinolite schist or altered basalt

Dark gray metamorphic rock fragment, likely slate or schist

Fine-grained foliated silicate rock; composition likely quartz, feldspar, mica, and/or chlorite