Metamorphic Or Igneous Alteration

Quartzite with Mica

Metamorphic Quartzite (SiO2 + Mica phyllosilicates)

Epidote

Epidote (Ca2(Al,Fe)3(SiO4)3(OH))

Unakite

Altered Granite (Granitic Metamorphic Rock)

Unakite

Unakite (Epidotized Granite)

Unakite

Epidotized Granite

Serpentine (Lizardite)

Serpentine subgroup, Mg3Si2O5(OH)4

Unakite

Unakite (Epidotized Granite)

Green Apophyllite and Stilbite on Quartz Cluster

Apophyllite-(K) (KCa4(Si8O20)(F,OH)·8H2O), Stilbite-Ca (NaCa4(Si27Al9)O72·28H2O), Quartz (SiO2)

Unakite

Unakite; epidote–pink feldspar–quartz rock

Unakit

Epidotized Granite

Quartzite with Chlorite / Epidote Inclusion

Metamorphic Quartzite (SiO2 with chlorite/epidote inclusions)

Banded Chert or Unakite-like Rock

Epidotized Granulite or Jasperoid Chert

Serpentine

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

Tumbled green-yellow stone, likely serpentine or nephrite jade

Serpentine-group mineral aggregate, commonly lizardite/antigorite; possible nephrite (interlocking tremolite-actinolite)

Glacial Granite with Epidote

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

Amazonite

KAlSi3O8 (Potassium Aluminum Silicate)

Seraphinite

Clinochlore (Mg,Fe2+)5Al(Si3Al)O10(OH)8

Banded gneiss (likely biotite-bearing)

Gneiss; quartz–feldspar–mica assemblage, with possible iron-oxide staining

Propylitic Altered Andesite

Hydrothermally Altered Andesite

Serpentine (likely antigorite-rich serpentinite)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with dark magnetite/chromite or pyroxene inclusions

Green serpentine or nephrite-like stone

Serpentinite, chiefly serpentine-group minerals; exact identification would require testing

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)

Rhyolite (likely porphyritic)

Rhyolite; chiefly quartz, alkali feldspar, plagioclase, and volcanic glass, with possible iron-oxide staining

Serpentine

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

Unakite

Unakite (altered granitic rock)

Weathered greenstone

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

Greenstone, possibly serpentine or altered basalt

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

Unakite-like jasper / epidote–feldspar rock

Epidote–feldspar–quartz aggregate; commonly marketed as unakite or brecciated jasper

Tumbled greenstone/chlorite-rich pebble

Likely chlorite-rich greenschist or altered basalt; exact identification requires testing

Quartz-rich rock with chlorite/epidote vein

Milky quartz with green chlorite or epidote; exact identification requires testing

Soapstone (Steatite)

Steatite (primarily Talc: Mg3Si4O10(OH)2)

Weathered gray stone, possibly basalt or granitic rock

Indeterminate fine- to medium-grained silicate rock; possible basalt, diabase, or weathered granite

Perlite (Unexpanded)

Amorphous volcanic glass

Unakite (polished/tumbled)

Unakite, a hydrothermally altered granite composed mainly of epidote, pink potassium feldspar (orthoclase/microcline), and quartz

Pale blue-gray quartz-rich pebble (tentative)

Quartz, SiO₂, possibly chalcedony or a weathered metamorphic fragment

Sodalite

Sodalite (Na8Al6Si6O24Cl2)

Epidote

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

Quartz-veined altered rock

Likely quartz-bearing metasediment or altered igneous rock; vein mineral: quartz (SiO₂)

Unakite

Altered Granite (Granitic Metamorphic Rock)