Metamorphic Or Igneous Alteration

Epidote in Basalt

Epidotized Basalt (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH) in Mafic Igneous Host)

Granitoid (with Epidote and Orthoclase)

Crystalline Felsic Intrusive Rock (containing SiO2, KAlSi3O8, and Ca2(Al2,Fe)(Si2O7)(SiO4)O(OH))

Unakite

Altered Granite (composed of orthoclase feldspar, green epidote, and quartz)

Polished pale-green stone, likely serpentine or jade

Serpentine-group mineral (commonly antigorite/lizardite), or possibly nephrite jade (tremolite–actinolite amphibole)

Polished tiger’s-eye

Tiger’s-eye, a chatoyant quartz variety (SiO₂), commonly pseudomorphic after crocidolite

Tumbled serpentine

Serpentinite; chiefly antigorite, lizardite, and chrysotile Mg₃Si₂O₅(OH)₄

Tiger’s eye

Quartz variety, primarily silicon dioxide (SiO₂); fibrous quartz pseudomorph after crocidolite asbestos

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Tumbled greenstone (likely serpentine or nephrite jade)

Serpentine-group minerals, chiefly antigorite/lizardite; possibly nephrite, a tremolite–actinolite amphibole aggregate

Likely green-gray serpentine-bearing rock

Serpentinite, dominated by serpentine-group minerals (antigorite/lizardite; Mg₃Si₂O₅(OH)₄), possibly with chlorite or talc

Uncertain greenish stone, possibly serpentine or altered basalt

Serpentine-group minerals, commonly Mg₃Si₂O₅(OH)₄; identification is provisional from the photograph

Unakite (likely), tumbled specimens

Unakite: epidote + pink potassium feldspar + quartz; composition varies and may include chlorite

Greenstone cabochon

Likely serpentinite or chlorite-rich greenschist; exact identification requires testing

Tumbled epidote-bearing rock (likely epidote–quartz–feldspar aggregate)

Epidote-rich metamorphic rock; minerals likely epidote (Ca₂(Al,Fe)₃Si₃O₁₂(OH), quartz, feldspar, and dark amphibole/biotite)

Unakite (likely tumbled)

Unakite; epidote–orthoclase–quartz aggregate

Tumbled serpentine or soapstone pebble

Serpentine-group minerals, chiefly antigorite/lizardite; possibly talc-rich steatite

Weathered greenstone (likely serpentinite or altered basalt)

Serpentinite, primarily Mg-rich serpentine minerals; possibly chlorite/actinolite-bearing altered mafic rock

Serpentine

Antigorite, Lizardite, or Chrysotile (Mg3Si2O5(OH)4)

Polished dark green stone (likely serpentine or greenstone)

Serpentine-group mineral aggregate, commonly antigorite/lizardite; identification is uncertain from the image

Serpentine

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

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals: (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)

Unakite

Unakite (altered granite)

Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

Tumbled greenstone pebble

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

Polished green serpentine (likely antigorite-rich)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible chlorite, magnetite, and talc

Basalt with Epidote (Greenstone)

Epidote-bearing Metabasalt

Green serpentine or nephrite jade fragment

Serpentine-group minerals, commonly antigorite/chrysotile; possibly nephrite (interlocking tremolite-actinolite)

Celadonite in Amygdaloidal Basalt

K(Mg,Fe2+)(Fe3+,Al)Si4O10(OH)2 (Celadonite mineral) within a Basalt matrix

Serpentinite (probable)

Serpentinite, a rock composed chiefly of serpentine-group minerals such as antigorite, lizardite, or chrysotile

Serpentine (Serpentinite)

Serpentinite (composed largely of serpentine group minerals: (Mg,Fe)3Si2O5(OH)4)

Weathered greenstone pebble (probable serpentinite or altered basalt)

Serpentinite-group rock, commonly dominated by antigorite/lizardite; identification is uncertain from the photograph

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Serpentine

(Mg,Fe)3Si2O5(OH)4

Unakite

Altered Granite (Epidotized Granite)

Serpentine

Antigorite, Lizardite, or Chrysotile; (Mg, Fe)3Si2O5(OH)4

Raw quartz-bearing mineral fragment

Quartz, silicon dioxide (SiO₂), possibly included or matrix-bearing

Granite

Phaneritic intrusive igneous rock

Rounded gray river pebble

Likely quartz-rich metamorphic or igneous pebble; exact identification requires testing

Epidosite with Quartz (Unakite-variant or Jasper)

Epidotized Metasomatite

Tumbled granite (likely granite or granitic gneiss)

Granite; chiefly quartz (SiO₂), feldspar, and mica, with possible alteration minerals

Weathered granite or granitic rock fragment

Granite; chiefly quartz, feldspar, and mica