Metamorphic (Low Grade)

Slate

Foliated Metamorphic Rock (composed primarily of silica and alumina with iron and magnesium)

Anthracite Coal

Anthracite (Carbon rank grade)

Jadeite

NaAlSi2O6 (Sodium Aluminum Silicate)

Small rounded green-gray pebble, likely greenstone

Greenstone (metamorphosed mafic rock; commonly chlorite- and epidote-bearing)

Schist (containing Muscovite Mica and Chlorite)

Mica Schist

Pyrite in Slate

Iron Disulfide (FeS2) in Low-grade Metamorphic Rock

Greenstone (likely chlorite schist)

Chlorite-rich metamafic rock; commonly chlorite + actinolite/epidote with quartz and feldspar

Water-worn pebble, likely greenstone

Greenstone (metamorphosed mafic volcanic rock; commonly chlorite-, actinolite-, and epidote-bearing)

Quartz on Chlorite Schist

Chlorite Schist (Mg,Fe)3(Si,Al)4O10(OH)2 with Quartz (SiO2)

Greenstone (likely serpentinite or altered basalt)

Serpentinite, chiefly serpentine-group minerals; possibly chlorite- or actinolite-bearing greenschist

Anthracite Coal

Anthracite (Metamorphic/High-grade Coal)

Serpentine (Serpentinite)

Serpentine group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4)

Slate

Slate; predominantly fine-grained phyllosilicates (muscovite/illite, chlorite) with quartz and feldspar

Weathered greenstone pebble

Likely metabasalt (chlorite–actinolite-rich greenschist); exact identification requires close examination

Serpentine (Serpentinite)

Serpentinite / Antigorite-Lizardite group (Mg,Fe)3Si2O5(OH)4

Slate

Slate, a fine-grained metamorphic rock composed mainly of mica-group minerals and quartz

Dark gray foliated metamorphic rock, likely slate or phyllite

Slate–phyllite; predominantly quartz, mica, and chlorite

Greenstone (Epidosite)

Epidosite (Metamorphosed Basalt/Diabase)

Greenstone (Epidote/Chlorite Rich Rock)

Metabasalt (often contains Epidote Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH))

Greenstone

Greenschist / Meta-basalt

Layered dark metamorphic rock, likely slate or phyllite

Slate/phyllite; predominantly fine-grained quartz, mica, and chlorite

Slate with Fossiliferous Impressions

Metamorphosed Argillaceous Rock (Fossiliferous Slate)

Pyrite-bearing dark slate or phyllite

Likely pyrite (FeS₂) disseminated in fine-grained slate/phyllite; exact host rock cannot be confirmed from the photo

Slate

Slate; fine-grained foliated metamorphic rock, chiefly quartz, mica, and clay minerals

Prehnite

Ca2Al(AlSi3O10)(OH)2

Wavellite

Wavellite (Al3(PO4)2(OH, F)3·5H2O)

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Epidotite (Unakite-related Epidote)

Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH))

Greenstone

Metabasalt / Greenschist

Lapis Lazuli (Low Grade)

Lapis Lazuli (Metamorphic rock containing lazurite, calcite, and pyrite)

Greenstone (likely chlorite-rich metamorphic rock)

Greenschist; commonly composed of chlorite, actinolite, epidote, and albite

Jadeite

Jadeite (NaAlSi2O6)

Greenstone

Greenschist (primarily composed of chlorite, actinolite, and epidote)

Epidote

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

Likely slate

Slate, a fine-grained metamorphic rock composed mainly of clay-derived mica minerals and quartz

Ruby in Zoisite (Anyolite) or possibly a dyed stone/agate

Anyolite (Ruby in green zoisite) or artificially altered chalcedony

Epidote

Epidote ({Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH))

Jadeite

NaAl(Si2O6)

Green Jade

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

Weathered slate fragment

Slate, a fine-grained metamorphic rock composed mainly of mica and chlorite, with quartz and feldspar

Jadeite Jade

NaAlSi2O6 (Sodium Aluminum Silicate)

Greenstone / Greenschist

Greenschist facies metamorphic rock (composed primarily of chlorite, actinolite, and epidote)